Assess the situation
Fill in what you know. Estimates are fine, exact numbers are better.
Emergency vet or poison control: which do I call?
Because effects are often delayed, the decision here is less about immediate collapse and more about getting ahead of a problem before it becomes severe.
Go straight to an emergency vet if…
- Your dog shows lethargy, pale or yellow (icteric) gums, weakness, rapid breathing, or dark urine, these can indicate hemolytic anemia already in progress
- The amount eaten was concentrated (powder, dehydrated flakes, soup mix, or bouillon) even in a small total weight
- Several days have passed since ingestion and your dog now seems unusually tired or is exercising less than normal
- A poison control consultation or your vet has told you to bring the dog in
Call poison control first if…
- Your dog just ate the food and currently shows no symptoms at all
- You need help estimating whether the amount and type is dangerous for your dog's specific weight
- You want guidance on what bloodwork (CBC, Heinz body smear) to request from your vet, and when
- You want a documented case number and monitoring plan you can hand to your regular vet
How onion and garlic toxicosis develops
Sulfur-containing compounds in onions and garlic cause oxidative damage to red blood cells, forming Heinz bodies. This process unfolds over days, not hours, which makes it easy to underestimate.
Cellular changes begin
- Heinz bodies (damaged hemoglobin clumps) begin forming and increasing in red blood cells
- Methemoglobinemia may begin to develop
- Usually no visible external symptoms yet
Peak methemoglobinemia
- Methemoglobin levels typically peak around this point
- Early signs may include lethargy or reduced appetite
Hemolytic anemia becomes apparent
- Lethargy, weakness, reduced appetite
- Rapid breathing and heart rate
- Pale or yellow (icteric) gums
- Dark or reddish urine (hemoglobinuria), which can also cause secondary kidney injury
- Exercise intolerance, collapse in severe cases
Published case data behind these estimates
These figures come from veterinary toxicology literature. They describe documented clinical thresholds, not a line between "safe" and "dangerous."
| Food and form | Documented threshold in dogs |
|---|---|
| Raw onion | ≈ 15–30 g per kg body weight |
| Garlic (raw, cooked, or powder) | Approximately 3–5x more toxic than onion per gram |
| Concentrated forms (dehydrated flakes, powder, soup mix) | Most dangerous per gram due to concentration |
This calculator applies a conservative multiplier to garlic and to concentrated/powdered forms of both foods to reflect their significantly higher potency per gram compared to fresh, raw onion. When the exact form is uncertain, choose the more concentrated category for a more conservative estimate.