Onion & Garlic Toxicity Calculator for Dogs

Onion toxicity occurs at 15-30 g/kg of body weight. To put that in perspective, a medium onion weighs about 150 g — meaning a single medium onion can be dangerous for a 10-15 lb dog. Japanese breeds (Akita, Shiba Inu) and mixed breeds with Asian heritage carry a genetic trait that makes their red blood cells significantly more sensitive to Allium toxins, so they can be affected at much lower doses. Always assume any onion ingestion is potentially serious, especially for these breeds.

Yes — garlic is about 5x more potent per gram than onion. While a toxic dose of onion is 15-30 g/kg, garlic reaches toxicity at roughly 3-6 g/kg. Onion and garlic powders are far more concentrated than their fresh forms: onion powder is approximately 5x more potent than fresh onion, and garlic powder is about 10x more potent than fresh garlic. This is why a small amount of powder in soup, seasoning, or baby food can be far more dangerous than a larger amount of raw vegetable.

Symptoms are often delayed — appearing 1-5 days after ingestion as red blood cells are progressively destroyed. Watch for weakness, lethargy, pale gums, rapid or labored breathing, exercise intolerance (reluctance to move or collapsing after mild activity), and dark or red-tinged urine (hemoglobinuria, a red-flag sign of severe anemia). Other signs include decreased appetite, vomiting, and diarrhea. A complete blood count (CBC) blood test is needed to confirm anemia and the presence of Heinz bodies on the red blood cells.