Dog and cat health guide
Is onion bad for dogs and cats in India: the dose per kilogram, why powder beats the bulb, and what to do about leftover sabzi
Western pages treat onion as an accident a dog has once. In an Indian kitchen it is the base of almost every savoury dish, so the exposure is daily and nobody counts it. This page gives the real numbers, the honest limits of the evidence on repeated small amounts, and the one gravy an Indian restaurant already makes that a dog can be near.
Quick answer
Is onion bad for dogs? Yes, and the dose is lower than most Indian owners expect. The MSD Veterinary Manual records clinical signs in dogs after 15 to 30 g of raw onion per kg of body weight, and the review literature puts consistent toxicosis above 0.5 per cent of body weight, which is 25 g for a 5 kg dog. Cats are worse, at 5 g per kg. Garlic is 3 to 5 times more toxic than onion, and dried onion is roughly six to seven times more concentrated than the fresh bulb.
This guide is general information for Indian pet owners and is not a diagnosis. Always consult a registered veterinarian near you before acting on anything you read here, and treat any sudden change in your pet's condition as urgent.
Is onion bad for dogs, and how much onion is actually too much
Onion is bad for dogs at a dose most Indian owners would not think twice about. The MSD Veterinary Manual records that ingestion of 15 to 30 g of raw onion per kg of body weight has resulted in clinical signs in dogs, and that toxicosis has been reported in cats after less than a teaspoon of cooked onions or 5 g/kg of raw onions. Those are the two numbers to hold, and the table below turns them into grams for an animal you can actually weigh.
A second figure sits beside them and it is lower. The review literature states that onion toxicosis is consistently noted in animals that ingest more than 0.5 per cent of their body weight in onions at one time. Half a per cent of body weight is 5 g per kg, which is a third of the bottom of the manual's dog range and the same as its cat figure. Both statements appear in the same paragraph of the same source, and they are not the same claim: 15 to 30 g/kg is the dose at which dogs in feeding studies showed measurable haematological change, while 0.5 per cent is the line above which reported cases cluster.
The American Kennel Club publishes the lower one for dogs without the caveat, saying it takes 100 grams of onion, about the size of a medium onion, per 20 kilograms of a dog's weight to cause toxic effects. That is 5 g/kg. So depending on which authority an Indian page has copied, the answer to "how much onion is toxic to dogs" moves by a factor of three to six, and almost no page says so.
One detail makes the confusion easier to see. The veterinary case literature gives 5 g/kg as the reported toxic dose for garlic in dogs, against 15 to 30 g/kg for onion. The number the AKC publishes for onion is therefore the same number the literature uses for garlic, which is several times more toxic by weight. We are not resolving that here, because we cannot. We are flagging it, so you know that a confident single figure on any page about this is a choice someone made rather than a fact everyone agrees on.
| Your animal | 0.5 per cent of body weight | That much fresh onion, as medium 100 g onions | MSD's own dog range, 15 to 30 g/kg | The same 0.5 per cent dose as dried onion or powder |
|---|---|---|---|---|
| 3 kg cat | 15 g | about one sixth of an onion | not applicable; the cat figure is 5 g/kg | about 2.3 g |
| 4 kg cat | 20 g | about one fifth | not applicable; the cat figure is 5 g/kg | about 3.0 g |
| 5 kg dog | 25 g | about one quarter | 75 to 150 g | about 3.8 g |
| 10 kg dog | 50 g | about one half | 150 to 300 g | about 7.6 g |
| 20 kg dog | 100 g | one whole onion | 300 to 600 g | about 15 g |
| 30 kg dog | 150 g | one and a half | 450 to 900 g | about 23 g |
Read the first column as the number that matters. A 5 kg Indian Spitz crosses the 0.5 per cent line at a quarter of one onion. Look at how much onion goes into one pan of gravy in your own kitchen and divide it by the number of servings, because a quarter of an onion is not a large share of that pan. A 30 kg Labrador has more room, and the room is one and a half onions, not a kitchen's worth.
The gram conversions in the last column are arithmetic on a published drying figure rather than a measurement, and the section on form shows the working. Treat every number here as a sense of scale, not as a licence to feed a dog any amount below it. The veterinary position is the one to act on: treatment is indicated after ingestion of any quantity.
Three respected sources put the line at 5 g/kg, 15 g/kg and 30 g/kg. Nobody puts it at zero, and nobody can tell you where your dog sits inside that spread, because susceptibility varies by individual and by breed. The only operating rule that works in an Indian kitchen is that no onion and no garlic go in the bowl, ever, in any form.
What onion and garlic actually do to a dog's blood
Onion and garlic destroy red blood cells by oxidising the haemoglobin inside them. Sulphur-containing oxidants in Allium species are released by mechanical disruption, which means chopping, cooking and chewing, and by the action of gut microbes on the material; absorbing them produces oxidative damage to red cells, Heinz body formation and methaemoglobinaemia, which begins within 24 hours and peaks at about 72.
The chemistry has a name and it is worth knowing, because it explains every practical rule further down this page. The principal toxin is n-propyl disulphide, which reduces the activity of glucose-6-phosphate dehydrogenase in red blood cells and so interferes with the regeneration of reduced glutathione, the molecule that normally prevents oxidative denaturation of haemoglobin. With that defence down, hydrogen peroxide accumulates and oxidises the sulphydryl groups of haemoglobin, and the denatured protein precipitates onto the inside of the cell membrane as a Heinz body.
A second compound does its own damage. Sodium n-propylthiosulphate, isolated from boiled onions, raises methaemoglobin and the Heinz body count and lowers glutathione; given orally to dogs at 500 micromoles per kg of body weight it produced haemolytic anaemia, with a ten-fold rise in oxidised glutathione in the red cells twelve hours after dosing.
Cells carrying Heinz bodies are fragile and the spleen and liver pull them out of circulation, which is extravascular haemolysis; others burst where they are. Oxidation of the globin chains in a different pattern produces eccentrocytes, cells whose haemoglobin has collapsed to one side, and eccentrocytosis is a major diagnostic feature of garlic-induced haemolysis in dogs. Meanwhile oxidised haem means methaemoglobin, which shifts the oxygen dissociation curve and leaves the blood carrying less oxygen even before enough cells have been lost to call it anaemia.
Why the signs arrive days after the meal
Signs lag because haemolysis lags. Clinical signs of Allium toxicosis are generally not noted until substantial haemolysis has occurred, usually a few days after exposure, and although Heinz bodies and methaemoglobin rise within 24 hours, the signs of anaemia may take as long as several days to appear. The experimental timeline matches. Six adult, clinically normal Pekingese dogs were fed cooked onions at 30 g/kg of body weight a day for two days; Heinz body counts rose dramatically from day 1 and peaked on day 3, while red cell counts, haemoglobin and haematocrit fell from day 1 and were significantly down by day 5.
That gap is why so many Indian owners never connect the two events. The sabzi was on Tuesday. The dog went quiet on Friday. Nobody in the house thinks about Tuesday.
In cases of recent ingestion, the breath of the affected dog or cat may smell of onion or garlic. If an animal is off its food and its breath smells of the kitchen, say so to the veterinary surgeon. It is a small observation that can save a day of diagnostics.
Why cats are hit harder than dogs, and the reason is their haemoglobin
Cats are the most susceptible species, followed by dogs. The reason is structural rather than behavioural: because of its molecular configuration, feline haemoglobin is approximately two to three times more prone to oxidative damage than that of other animals, and other enzymatic factors increase feline dependence on glutathione for oxidative protection compared with other mammals.
Dogs are not well defended either, which is why they sit second on that list. Catalase antioxidant activity in dog red cells is low, and the review literature independently puts normal feline haemoglobin at about two to three times more susceptible to oxidative damage than the haemoglobin of other species, which is the same figure from a second source. Humans are the most resistant species studied, and that is the whole reason an onion is dinner for the family and a poison for the animal under the table.
The clearest cat evidence is also the most uncomfortable, because the dose is tiny and the exposure was daily. Forty-two healthy adult specific-pathogen-free cats were studied; for the dose-response arm, five groups of six cats were fed a canned diet for two months containing 0, 0.3, 0.75, 1.5 or 2.5 per cent onion powder, and the rate and degree of Heinz body formation differed significantly between the concentrations. In the baby-food arm, cats eating onion powder had significantly higher Heinz body percentages, peaking at 33 to 53 per cent, and the 2.5 per cent diet caused a significant fall in packed cell volume.
Note what that study is. It is not a cat raiding a plate of biryani. It is onion powder as a small, measured fraction of the daily diet, fed for two months, and at the lowest concentration tested, three parts per thousand, the blood still changed. The authors concluded that baby food or other foods containing similar amounts of onion powder should be avoided for cats, and that cats with diseases associated with oxidative stress may develop additive haemoglobin damage.
The complication that makes a cat harder to diagnose
A small number of Heinz bodies are often found in feline red cells normally, so the count has to be interpreted alongside the history and the severity of anaemia rather than read on its own. Several common feline disorders raise Heinz bodies by themselves, including diabetes mellitus, particularly with ketoacidosis, hepatic lipidosis, hyperthyroidism and lymphoma. A cat can also inherit a haemolytic anaemia, which Bonbeno covers separately on pyruvate kinase deficiency in cats.
That is a reason to tell the veterinary surgeon what the cat ate, not a reason to assume a smear will sort it out. The history is half the diagnosis.
A cat is almost never handed an onion. It is handed the chicken out of the family's curry, cooked in an onion and garlic base, and the exposure repeats for as long as the habit does. Our guide to homemade cat food in India sets out what a cat's bowl should hold instead, and the cat diet chart for India does the portion arithmetic.
Raw, cooked, fried, dried, powdered: which form matters most
Concentrated forms matter most, and cooking does not help. Toxicosis in dogs and cats is most commonly associated with ingesting concentrated forms of Allium such as dehydrated flakes, powders or dry onion soup mixes. The manual's own framing is that the packet, not the bulb, is what most reported poisonings involve.
Cooking is the first assumption to drop. The compound sodium n-propylthiosulphate was isolated from boiled onions, not raw ones, and the Pekingese feeding study that confirmed haemolytic anaemia used cooked onions. The manual lists raw, cooked, dehydrated and granulated onions and garlic as forms that have affected dogs and cats, without ranking cooking as any safer. Boiling a gravy changes nothing a red cell can detect.
Processing may make it worse. In a 2025 in vitro study, canine red cells were incubated with ethanol extracts of fresh, dried and granulated garlic; granulated garlic produced Heinz bodies in about 15.0 per cent of cells against 5.0 per cent for fresh garlic, and the authors concluded that drying and granulation may enhance the release of reactive compounds. One honest caveat belongs with that figure: in the same study the dried garlic group's Heinz body count sat close to control levels even though the authors' overall conclusion grouped dried with granulated, so the two endpoints in that paper do not fully agree, and the work is in a test tube rather than in a dog.
The arithmetic of a dried bulb
Drying concentrates an onion roughly six to seven times by weight, and the sum is simple. Onions are generally dried from an initial moisture content of about 86 per cent down to 7 per cent or less. One hundred grams of fresh onion therefore holds 14 g of dry matter, which at 7 per cent moisture becomes about 15 g of dried product, so one gram of onion powder carries the material of about 6.6 grams of fresh onion.
Apply that to the first table and the Indian kitchen changes shape. The 0.5 per cent line for a 5 kg dog is 25 g of fresh onion, which is under 4 g of onion powder. For a 4 kg cat it is 20 g fresh, which is about 3 g of powder. Three grams is not a spoon of masala; it is less than one.
Two Indian product categories deserve naming for that reason, and you can check both tonight. Onion powder, garlic powder and dehydrated onion appear in the ingredient lists of many ready masala blends and instant gravy pastes, and the whole point of a stock cube or a soup sachet is that a tiny weight flavours a litre. A dog that licks out an empty soup sachet or chews a masala packet has eaten something far closer to the published dose than a dog that steals a slice of onion.
Open the masala drawer and read the back of three packets. If any lists onion powder, garlic powder, dehydrated onion or onion solids, that packet belongs in a closed container on a high shelf, not in a low drawer a dog can nose open. The concentrated forms are the ones the veterinary manual links most often to actual poisoning.
The Indian pattern: leftover sabzi, dal tadka and biryani, every day
The Indian exposure is chronic rather than accidental, and that is what makes this page different from a Western one. Indian households consumed 193.61 lakh metric tonnes of onion in 2022-23, a figure the Government of India calculates from the Household Consumption Survey, against a national production of 242.12 lakh metric tonnes in 2023-24. That household figure is 19.361 million tonnes a year, which divided by 365 is roughly 53,000 tonnes of onion entering Indian homes every single day.
Onion is not an ingredient here, it is the floor the dish is built on. The same government annexure shows how evenly it is spread: by household consumption, Uttar Pradesh took 27.64 lakh metric tonnes, Bihar 20.88, Maharashtra 17.13, Tamil Nadu 14.32 and West Bengal 14.23, while on the production side Maharashtra grew 86.02 lakh tonnes, Madhya Pradesh 41.66, Gujarat 20.57 and Karnataka 16.38. There is no Indian region where the family pot is reliably onion-free.
So the question an Indian owner needs answered is not "what if my dog eats an onion". It is "what is the daily tadka doing". The table below is where the Allium actually sits, and the honest answer to the daily question follows it.
| Where it is | Which Allium, and in what form | What to do |
|---|---|---|
| Leftover sabzi, dal with tadka, rajma, chhole, any gravy | Fresh onion and garlic, chopped and cooked, so the oxidants are fully released | Never into the bowl. This is the commonest route and the one worth changing first |
| Biryani, pulao, fried rice, the rice under a curry | Fried onion through the rice and often whole garlic | Never. Picking the pieces out does not remove what has leached into the rice |
| Chicken or mutton lifted out of the family curry | Whatever was in the gravy, carried on the meat | Never. Cook the animal's protein plainly and separately |
| Ready masala blends, instant gravy pastes, soup sachets, stock cubes | Dried onion and garlic powder, the most concentrated forms | Closed container, high shelf. A chewed sachet is a same-day veterinary call |
| Ginger-garlic paste in the fridge door | Raw garlic at full strength, in a jar at nose height | Move it up. A dog that gets the jar open has eaten pure Allium |
| Chivda, namkeen, bhujia and other fried savouries | Onion and garlic powder in the seasoning | Off low tables, especially during festival weeks |
| Papad, chutney, achar and raita | Garlic in many chutneys and achars, onion in many raitas | Treat as curry. None of it belongs on an animal's plate |
| Chopping board scraps, peels and the vegetable bin | Raw onion and garlic skins and offcuts | Covered bin the animal cannot open, cleared after cooking |
What repeated small amounts do and do not establish
Repeated small amounts are an established route to toxicosis, and no published figure tells you how small is safe. The review states plainly that this type of toxicosis is typically caused by consumption of a single large quantity of plant material or repeated small amounts, and that daily feeding of onions could have a cumulative effect through ongoing formation of Heinz bodies, as against a single exposure with a wide gap until the next one, which allows the bone marrow to regenerate the prematurely destroyed red cells. It also records that a relatively high dose of 600 to 800 g in one meal, or spread apart over a few days, can damage red blood cells and cause haemolytic anaemia.
The strongest direct evidence for the chronic pattern is the cat work already quoted, where 0.3 per cent onion powder in the diet for two months changed the blood. The strongest counterweight is a dog study. Four of eight healthy adult mixed-breed dogs were given 1.25 mL of garlic extract per kg of body weight, equal to 5 g of whole garlic per kg, intragastrically once a day for seven days; red cell count, haematocrit and haemoglobin fell to a minimum on days 9 to 11, Heinz bodies and eccentrocytes appeared, and no dog developed haemolytic anaemia.
Hold both of those. For a 10 kg dog, that study is 50 g of garlic a day for a week, a dose no household would ever feed, and it damaged the blood without tipping into clinical disease. That is the ceiling evidence, and it says the dog has some margin. What no study has done is feed a dog the realistic Indian dose, a ladle of onion-based gravy most days for a year, and measure what happens.
- Established: repeated small amounts of Allium can cause toxicosis, not only a single large meal.
- Established: daily exposure denies the bone marrow the gap it needs to replace destroyed red cells, which is the mechanism by which a cumulative effect would work.
- Established: onion powder at 0.3 per cent of the diet measurably changed cats' blood over two months.
- Not established: any threshold below which a daily Indian gravy is safe for a dog or a cat. No figure of that kind exists for any species.
- Not established: that small daily amounts produce the same anaemia as one large dose. Several Indian pages assert this; the published dog study at 5 g/kg of garlic daily for a week found oxidative damage and no haemolytic anaemia.
The practical reading is uncomfortable but clear. A dog on daily leftover sabzi is not obviously about to collapse, and it is accumulating oxidative damage nobody is measuring, on a mechanism that is documented, with no safe level published anywhere. That is the situation in a very large number of Indian homes, and it deserves to be stated rather than smoothed over.
Garlic, and the tick remedy that has never been tested on a dog
Garlic is 3 to 5 times more toxic than onion by weight. The toxic dose in dogs is reported as 5 g/kg for Allium sativum against 15 to 30 g/kg for Allium cepa, so for a 10 kg dog that is 50 g of garlic. In the 2026 case report below, two raw cloves weighed about 16 g together, which puts 50 g at roughly six cloves of that size.
That ratio is what makes the tadka the problem rather than the salad. An Indian gravy base is onion and garlic together, so a single serving carries two Allium species at once, one of them several times more potent than the other, and both already released by the chopping and the cooking.
Garlic also does something onion does not. Allicin and ajoene, the pharmacologically active agents in garlic, are potent cardiac and smooth muscle relaxants, vasodilators and hypotensive agents, and garlic preparations that have not been aged cause direct damage to the gastric and ileal mucosa, resulting in pain and diarrhoea. A hypotensive effect layered on top of anaemia and impaired oxygen transport is not a helpful combination.
One case that disagrees with every published dose
A 2026 case report records a fatal garlic toxicosis in a dog at a quantity far below the reported toxic dose, and it belongs here precisely because it does not fit. A three-year-old female mongrel of about 20 kg was submitted for post-mortem examination in Turin after gastrointestinal signs including vomiting; at necropsy, food residues and two raw garlic cloves weighing about 16 g in total were found in the stomach. Sixteen grams in a 20 kg dog is 0.8 g/kg, roughly one sixth of the 5 g/kg figure.
Histopathology showed multifocal myocardial haemorrhages, diffuse pulmonary capillary congestion, hepatic sinusoidal dilation with haemorrhage, splenic haemorrhage and renal glomerular capillary dilation, consistent with systemic hypoxic and vascular injury secondary to oxidative erythrocyte damage, and toxicological screening for rodenticides, organophosphates, carbamates and metaldehyde was negative. The authors are careful about what they have: the lower quantity of garlic recovered compared with reported toxic doses suggests possible individual susceptibility or incomplete recovery of ingested material, and no blood was taken before death, so there is no Heinz body count.
One dog is not a dose threshold and this page will not pretend otherwise. What it is, is a published reminder that the thresholds in the first table describe populations and that individual animals vary. Susceptibility is known to vary by inheritance: dogs with hereditary high erythrocyte reduced glutathione and circulating potassium are more susceptible to the haematological effects of onions, and that trait is relatively common in Japanese breeds such as the Akita and the Shiba Inu Salgado BS, Monteiro LN and Rocha NS. Other inborn errors of metabolism or nutritional deficiencies that lower red cell antioxidant defences, such as glucose-6-phosphate dehydrogenase deficiency or zinc deficiency, could raise an animal's susceptibility too.
Garlic for ticks and fleas: what the evidence says
Garlic has never been shown to prevent, repel or kill fleas on a dog, because no study has ever tested it properly. A peer-reviewed Knowledge Summary published by RCVS Knowledge asked exactly that question and searched PubMed, Web of Science, CAB Abstracts and Scopus from their start dates to 3 December 2019; the four databases returned five results in total, every one was excluded as not addressing the question, and the total number of relevant papers was zero.
Widening the criteria did not rescue it. Including garlic applied environmentally, or case studies based on oral, topical or environmental application, also yielded no results, and the author concluded that there is a lack of peer-reviewed scientific in vivo evidence to address the question. The nearest relevant work was a 1984 in vitro study by Renapurkar and Deshmukh, which applied garlic extract in a hexane solvent to filter paper and found a kill concentration similar to that of several organochlorine and organophosphorus insecticides; the summary states plainly that external validity to a live dog should not be inferred from those findings.
There is garlic ectoparasite evidence in other species, including reductions in tick burden in cattle given 100 g or 200 g a day and reductions in poultry mite infestation, and the author notes this may suggest a tentative basis for clinical research in dogs; until garlic has been shown to work against fleas in dogs at levels non-toxic to the dog, the recommendation is to use an ectoparasiticide that has been demonstrated to work.
Indian tick counts peak through the hot and humid months from March into the monsoon, which our tick prevention for dogs in India guide sets out with the Indian surveys behind it. That is exactly when owners reach for a home remedy. Feeding a daily dose of the most toxic Allium to a dog, in the season when it is most likely to be fighting a tick-borne infection that destroys red cells anyway, is the opposite of help. Use a demonstrated ectoparasiticide, and see cat ticks and fleas in India for the feline side.
Every Allium in an Indian kitchen, and the one spice that is not one
Seven Alliums reach an Indian kitchen routinely and one famous substitute is not an Allium at all. The genus includes onion, garlic, leek, chives, shallots and scallions, and was reclassified out of Alliaceae into the subfamily Allioideae of the family Amaryllidaceae. All Allium species and their derivatives can be toxic to dogs and cats.
Spring onion earns its own line because the clearest small-animal case report in the literature is about it. Two dogs in Catalonia developed Heinz body anaemia after eating the leftovers of a meal of grilled calcots, which are Catalan spring onions. A 14-month-old 4.2 kg smooth-haired Dachshund presented with dark urine and anorexia the day after eating them; its haematocrit was 40.7 per cent at presentation, fell to 24.7 per cent four days later with haemoglobin at 7.0, and a blood smear showed widespread Heinz bodies before it made a full recovery.
The second dog is the one that matters more for India. A 9-year-old 38 kg Siberian Husky was admitted six days after eating the leftovers, having refused food for three days; its haematocrit was 15.4 per cent, haemoglobin 5.9 g/dl, and it needed a transfusion of packed red blood cells before recovering over 72 hours in hospital. A 38 kg dog, leftovers, six days of silence, then a transfusion.
| What you call it | Botanical name as the sources give it | Family | Verdict |
|---|---|---|---|
| Onion, pyaz, kanda | Allium cepa | Amaryllidaceae, subfamily Allioideae | Toxic. 15 to 30 g/kg has produced clinical signs in dogs, 5 g/kg in cats |
| Garlic, lehsun | Allium sativum | Same | Toxic, and 3 to 5 times more so than onion by weight |
| Spring onion, hara pyaz | Allium cepa, eaten young | Same | Toxic. Two dogs developed Heinz body anaemia on leftovers, one needing a transfusion |
| Shallot, small sambar onion | Named in the genus by the review, no separate species figure | Same | Toxic. Treat it as onion |
| Leek | Allium porrum in the review, Allium ampeloprasum in current usage | Same | Toxic. Named among the species of toxicological interest |
| Chives | Allium schoenoprasum | Same | Toxic. Named among the species of toxicological interest |
| Chinese or garlic chives | Allium tuberosum | Same | Toxic. A dog developed Heinz body anaemia with eccentrocytosis after eating it with garlic |
| Asafoetida, hing | Oleogumresin of Ferula species | Apiaceae, the carrot family | Not an Allium. The Allium mechanism does not apply, and no veterinary dose exists either way |
Hing is not an onion, and that matters more than it sounds
Hing is a plant resin from a completely different family, so the Allium mechanism does not apply to it. India's own food standard defines asafoetida, hing or hingra, as the oleogumresin obtained from the rhizome and roots of Ferula alliaces, Ferula rubricaulis and other species of Ferula, and sets its limits at not more than 15 per cent total ash and not more than 1 per cent starch. Ferula is in the carrot family, not in Amaryllidaceae, and it contains no n-propyl disulphide.
What most Indian households actually buy is compounded hing, and the standard covers that too: compounded asafoetida, or bandhani hing, is composed of one or more varieties of asafoetida, Irani or Pathani hing or both, together with gum arabic, edible starches or edible cereal flour. So a block of supermarket hing is mostly starch or cereal flour carrying a little resin, which is worth knowing if your dog has a diagnosed wheat problem, and is irrelevant to Allium toxicity.
This is not a licence to feed hing to a dog. No published veterinary dose for asafoetida in dogs or cats exists, and we could not find one on 21 October 2026. The useful conclusion is narrower and more practical, and it is in the leftovers section.
Hing smells sulphurous and tastes like cooked onion, which is exactly why cooks use it as a substitute. The resemblance is in the aroma chemistry, not in the botany, and a red blood cell responds to the specific organosulphur compounds in Allium rather than to anything that smells similar.
Symptoms of onion and garlic poisoning, and when it is an emergency
The first symptoms are usually gastrointestinal and the dangerous ones come later. Vomiting, diarrhoea, abdominal pain, loss of appetite, depression and dehydration come first; it then takes a few days for the signs of red cell loss to appear, which are pale mucous membranes, a rapid respiratory rate, difficulty breathing, lethargy, dark coloured urine that is reddish or brown, jaundice, weakness and a rapid heart rate.
The manual's own list of what may occur runs lethargy, anorexia, tachypnoea, tachycardia, weakness, exercise intolerance, icterus, haemoglobinuria, collapse and death. Depression, exercise intolerance and cold sensitivity are also reported.
- Go now, not tomorrow: pale or white gums, yellowing of the gums or the whites of the eyes, collapse, or breathing that is fast at rest.
- Go today: urine that is red, brown or the colour of tea; a dog or cat that is suddenly exercise intolerant or unwilling to stand.
- Call today: any known ingestion of onion, garlic or a concentrated powder, whatever the animal looks like, because treatment is indicated after ingestion of any quantity.
- Mention it at the next visit: an animal that has been fed leftovers containing onion or garlic for months and seems well. It is not an emergency and it is a conversation the veterinary surgeon should have the facts for.
The Indian differential nobody mentions
Pale gums, dark urine and jaundice have more than one cause, and in India tick-borne disease sits high on the list. Babesiosis and leptospirosis belong in the differential for jaundice alongside Allium toxicosis, and an Indian clinician will reasonably reach for a blood smear and a tick history first. In the Catalan spring onion case, the supravital stain that confirmed abundant Heinz bodies also showed no parasites, and ruling the parasites out is what settled the diagnosis.
Bonbeno covers those conditions in full on babesiosis in dogs and tick fever in dogs in India. The point for an owner is simple. If you volunteer the food history, the clinician can test for both instead of chasing one.
One drug interaction is worth knowing because the drugs are in every Indian medicine drawer. Concurrent treatment with substances that induce red cell oxidative injury or reduce its defences, including paracetamol, propofol, propylene glycol, sulphonamides, large doses of vitamin K3 and benzocaine, is likely to increase an animal's susceptibility to Allium toxicosis. Never give a pet a human painkiller, and tell the veterinary surgeon about anything already given.
What to do if your dog or cat has eaten onion or garlic
To act correctly after an Allium exposure, telephone a veterinary surgeon immediately and do nothing else yourself. There is no antidote; management is early gastrointestinal decontamination performed by a clinician, oxygen or a blood transfusion if needed, and intravenous fluid therapy to protect the kidneys against haemoglobinuric nephrosis.
Do not try to make the animal vomit at home. Emesis is induced with prescription drugs under veterinary supervision, and the choice of drug differs between dogs and cats. Bonbeno names no emetic, no dose and no antidote on this page on purpose; those are decisions made on the individual animal by the clinician examining it, which is why this page publishes under the medical disclaimer.
- Take the food away from the animal and keep the rest of it, because the ingredient list or the dish itself is the only record of what was eaten.
- Weigh the animal, or use its last recorded weight, since every dose on this page is per kilogram of body weight.
- Estimate the amount in grams or in pieces rather than describing it as a little, and note the time to the nearest fifteen minutes.
- Telephone your veterinary practice and say the words onion or garlic, the form it was in, the amount and the time.
- Go in if you are told to, and ask specifically whether the blood should be rechecked over the following days rather than once.
Ask about the recheck, because the timing of the disease makes a single blood test misleading. It is important to monitor the red cells of affected animals for several days after ingestion, since that is when the anaemic nadir usually occurs. A normal result two hours after the meal has told you very little.
India has no national 24-hour animal poison line that we could find on 21 October 2026, which makes your own veterinary practice the first and only call. A 24-hour veterinary hospital is a realistic option in Mumbai, Delhi, Bengaluru, Chennai, Hyderabad, Pune and Kolkata, and is not in most of the country. Save both numbers in your phone this week rather than searching for them at 11 pm.
Antioxidants such as sodium ascorbate, vitamin E and acetylcysteine have minimal protective effects on onion powder toxicosis in cats. Home dosing with a vitamin is not treatment. Salt water as an emetic is dangerous in its own right. Whatever you read in a WhatsApp group, the useful action is the phone call.
What to actually do about leftovers in an Indian kitchen
To keep Allium out of your animal without reorganising your cooking, separate the dog's food from the family's at the point the tadka goes in, not at the point the plate is cleared. That single change removes almost every exposure route described on this page, and it costs one extra bowl.
Most Indian households are not going to stop using onion and garlic, and no page should pretend otherwise. What is realistic is taking the animal's portion out before the gravy exists.
- Lift the dog's share of rice, roti, dal or boiled vegetable out of the pan before the tadka goes in, which takes ten seconds and ends the problem at source.
- Cook the animal's protein separately and plainly, boiled or steamed, with no salt, no masala and no oil from the family pan.
- Scrape leftover gravy into the bin rather than onto the dog's plate, and put the bin where the dog cannot open it.
- Store masala powders, soup sachets, instant gravy pastes and garlic paste in a closed container on a high shelf, since those are the concentrated forms.
- Brief the household and any help who cooks, once and clearly, because the person who feeds the dog leftovers is usually not the person who read this page.
The one Indian gravy that is already built for this
Indian cooking has an entire no onion no garlic tradition and it is the only culinary shortcut this page can honestly offer. Jain, satvik and many temple kitchens cook without any Allium at all and use hing to carry the savoury note instead, which is why hing matters practically rather than merely botanically. If you cook that way, or if someone in your household does during a fast, a plain portion from that pot carries no Allium risk at all.
That is also the most useful thing to say to a restaurant. Asking for a Jain preparation is a request Indian kitchens understand instantly and it means no onion and no garlic. It is not a pet-safety claim, it is a kitchen instruction that happens to remove the hazard, and our guide to feeding a dog in a vegetarian household covers the wider question of what such a kitchen can and cannot feed an animal.
A plain portion still is not a complete diet. Removing the onion fixes a toxicity problem and leaves a nutrition problem, and the two need different answers. Our guides to homemade dog food in India and the dog diet chart for India set out what a complete bowl requires once the hazard is out of it.
Community dogs deserve a line, because leftover curry is the commonest thing anyone gives them. A street dog has nobody to notice dark urine on day four. Plain rice, plain roti, a boiled egg and clean water are the right gift, and our guide to feeding community dogs in India covers the practice and the law around it.
Festival weeks are when every rule slips, and that is a separate page. Our guide to Diwali sweets and your dog handles the mithai side of the same problem, including the chivda and namkeen bowls that carry onion and garlic powder into the living room at dog height.
An animal that has eaten onion-based leftovers for a long time and seems well is not an emergency and is worth mentioning at the next appointment. Stop the exposure, because there is no established safe level, and ask whether a blood count is worth running as a baseline. Guilt is not useful here. The daily tadka is a food hazard almost nobody in India is warned about, and the warning that does exist is written for a country where onion is a garnish.
Common questions
How much onion is toxic to dogs?
The published figures disagree, so hold the range. The MSD Veterinary Manual records clinical signs in dogs after 15 to 30 g of raw onion per kg of body weight, while the review literature says toxicosis is consistently noted above 0.5 per cent of body weight eaten at one time, which is 5 g per kg. For a 10 kg dog that spread runs from 50 g, about half a medium onion, to 300 g. The AKC publishes the lower figure as 100 grams per 20 kilograms.
What happens if a dog eats a small bit of onion?
Usually nothing visible, and that is the trap rather than the reassurance. Oxidative damage to red cells and Heinz body formation begin within 24 hours and peak at about 72, while haemolysis typically occurs 3 to 5 days after exposure, so a dog that looks fine on the evening of the meal has told you nothing. A single small piece in a large dog is unlikely to reach a published threshold, but the veterinary position is that treatment is indicated after ingestion of any quantity, so telephone rather than wait.
Can dogs eat onion powder?
No, and onion powder is the worse form rather than the milder one. Toxicosis in dogs and cats is most commonly associated with concentrated forms of Allium such as dehydrated flakes, powders and dry onion soup mixes. Drying takes an onion from about 86 per cent moisture down to 7 per cent or less, so one gram of powder carries the material of roughly 6.6 grams of fresh onion. For a 5 kg dog, under 4 grams of powder reaches the same 0.5 per cent of body weight line as a quarter of a fresh onion.
Is a little bit of garlic powder ok for dogs?
No. Garlic is 3 to 5 times more toxic than onion by weight, and the dried and granulated forms are the ones the veterinary manual links most often to actual poisoning. A 2025 in vitro study found granulated garlic produced Heinz bodies in about 15 per cent of canine red cells against 5 per cent for fresh garlic, and concluded that drying and granulation may enhance the release of the reactive compounds. There is no published amount of garlic powder that is established as safe for a dog of any weight.
What will happen if a dog eats garlic?
Garlic oxidises the haemoglobin inside the dog's red blood cells, producing Heinz bodies and eccentrocytes and, at enough of a dose, haemolytic anaemia. Garlic also contains allicin and ajoene, which are vasodilators and hypotensive agents, and unaged garlic preparations directly damage the stomach and ileal lining, causing pain and diarrhoea. Signs of anaemia typically appear several days later rather than at the time, so the lack of an immediate reaction means nothing.
How quickly does garlic poisoning show in dogs?
Slowly, which is exactly why it gets missed. Heinz bodies and methaemoglobin rise within 24 hours of ingestion, but the clinical signs of anaemia may take as long as several days to appear, and haemolysis typically occurs 3 to 5 days after exposure. In the experimental garlic study, the red cell count, haematocrit and haemoglobin of the dosed dogs reached their minimum on days 9 to 11. Early gastrointestinal signs such as vomiting can come sooner, from the direct effect on the gut lining.
What happens if a cat eats a little onion?
A little goes further in a cat than in a dog. Toxicosis has been reported in cats after ingesting less than a teaspoon of cooked onions or 5 g per kg of raw onions, which for a 4 kg cat is about 20 grams, roughly one fifth of a medium onion. Feline haemoglobin is about two to three times more prone to oxidative damage than that of other animals because of its molecular configuration, and cats depend more heavily on glutathione for oxidative protection.
Is onion very toxic to cats?
Yes. Cats are the most susceptible species to Allium toxicosis, ahead of dogs. In a controlled study, five groups of six cats were fed a canned diet for two months containing 0, 0.3, 0.75, 1.5 or 2.5 per cent onion powder, and the rate and degree of Heinz body formation differed significantly between those concentrations, with the 2.5 per cent diet causing a significant fall in packed cell volume. Even three parts per thousand of onion powder in the daily diet changed the blood.
How long does it take for onion poisoning to show in cats?
Several days in most cases, and longer if the exposure is a small daily amount rather than one meal. Heinz body formation and methaemoglobin begin within 24 hours and peak at about 72 hours, while haemolysis typically occurs 3 to 5 days after exposure. Cats normally carry a small number of Heinz bodies anyway, so a vet reads the count alongside the history and the severity of the anaemia rather than on its own, which is why telling them what the cat ate matters.
How to treat onion toxicity in cats?
Treatment is veterinary and supportive, because no specific antidote for Allium toxicosis exists. Management involves early gastrointestinal decontamination performed by a clinician, oxygen supplementation or a blood transfusion where needed, and intravenous fluids to protect the kidneys. Do not attempt to make a cat vomit at home. Antioxidants such as sodium ascorbate, vitamin E and acetylcysteine have minimal protective effects on onion powder toxicosis in cats, so home dosing with a vitamin is not treatment.
Is hing or asafoetida safe for dogs?
Hing is not an Allium, so nothing on this page about onion and garlic applies to it. India's food standard defines asafoetida as the oleogumresin of Ferula species, which sit in the carrot family rather than in the onion family, and compounded bandhani hing is that resin blended with gum arabic, edible starch or cereal flour. That is not the same as proving hing safe for dogs, because no veterinary dose exists either way. Its real value is that a no onion no garlic kitchen uses it instead of a tadka.