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Dog garlic toxicity calculator
The Merck Veterinary Manual says garlic is 3–5 times more toxic than onion. Enter your dog's weight and how much garlic it ate to compare with the amounts likely to cause poisoning.
The result and what to do next will show here.
A guide for deciding how urgently to call, not a diagnosis. If in doubt, call your vet. Last reviewed October 7, 2026.
How much garlic is toxic to dogs?
The Merck Veterinary Manual reports poisoning signs in dogs after 15–30 g of raw onion per kg of body weight, and says garlic is 3–5 times more toxic than onion. That puts the danger zone for garlic at roughly 3–10 g per kg of body weight. These garlic figures are our estimate from Merck's numbers, not a measured dose, and some dogs react to less.
| Dog's weight | Estimated danger range | About this many cloves |
|---|---|---|
| 10 lb (4.5 kg) | 14–45 g | 5–15 |
| 20 lb (9 kg) | 27–91 g | 9–30 |
| 40 lb (18 kg) | 54–181 g | 18–60 |
| 60 lb (27 kg) | 82–272 g | 27–91 |
| 80 lb (36 kg) | 109–363 g | 36–121 |
| 100 lb (45 kg) | 136–454 g | 45–151 |
Cloves are counted at 3 g each, the USDA reference weight. Cloves vary in size, so the same number of big cloves can be a bigger dose.
Repeated amounts matter too. In a 2000 study by Lee and colleagues, dogs given the equivalent of 5 g of fresh garlic per kg daily for a week developed red blood cell damage (Heinz bodies and lower red cell counts), although none showed signs of anemia. Don't add garlic to your dog's food or treats.
Why garlic is dangerous
Garlic, like onion, leeks and chives, contains compounds that damage red blood cells and can cause anemia. Damage starts within a day, but the anemia usually shows 3–5 days after eating, so a dog can seem fine at first. Cooking does not make garlic safe, and powders, granules and dried flakes are more concentrated than fresh garlic.
Some dogs are more sensitive than others. The Pet Poison Helpline lists Japanese breeds such as the Akita and Shiba Inu as more sensitive to garlic and onion, and cats are also more sensitive. For onion, or for a cat, use the onion and garlic toxicity calculator.
What to do if your dog ate garlic
- Work out what and how much was eaten, and when. Keep the packaging or recipe.
- Call your vet or a pet poison line, even if your dog seems well.
- Don't make your dog vomit unless a vet tells you to.
- Watch for vomiting, diarrhea, weakness, pale gums, fast breathing and red-colored urine over the next several days.
Questions people ask
How much garlic is toxic to a dog?
Using the Merck Veterinary Manual's onion figures, we estimate that roughly 3–10 g of garlic per kg of body weight is enough to cause poisoning. For a 40 lb dog that's about 54–181 g, or 18–60 average cloves. Garlic powder is more concentrated, so less is needed.
Will one clove of garlic hurt my dog?
For most medium and large dogs, one 3 g clove is well below the amounts linked to poisoning, though it may upset the stomach. For a very small dog it's a bigger share of body weight, so enter the weight above to check.
Is cooked garlic safe for dogs?
No. Raw, cooked, dried and powdered garlic are all toxic. Dried and powdered forms are more concentrated than fresh.
How long after eating garlic will a dog show symptoms?
Stomach upset can come first. Signs of anemia, such as weakness, pale gums and red urine, usually appear 3–5 days after eating garlic.
Is garlic worse than onion for dogs?
Yes. The Merck Veterinary Manual says garlic is 3–5 times more toxic than onion.
Sources
- Merck Veterinary Manual: Allium spp Toxicosis in Animals
- VCA Animal Hospitals: Onion, Garlic, Chive, and Leek Poisoning in Dogs
- Pet Poison Helpline: Garlic
- Beleć et al., Animals (2025), review citing Lee et al., Am J Vet Res 2000;61:1446–50
- USDA FoodData Central: Garlic, raw (portion weights)