Allium sativum
Why is it risky?
Garlic contains organosulfur compounds (including allicin and related thiosulfinates) that cause oxidative damage to feline red blood cells, producing Heinz body hemolytic anemia. Cats are more sensitive to Allium toxins than dogs, garlic is approximately 5 times more potent per gram than onion. All forms are toxic: raw, cooked, powdered, and dehydrated. Garlic powder is particularly dangerous due to its concentrated nature.
Affected Systems
Digestive · Cardiovascular
Symptoms
Vomiting, diarrhea (early). Delayed 2–5 days: lethargy, weakness, pale or yellowish gums, rapid breathing, reddish-brown urine, collapse. Hemolytic anemia develops silently after the initial GI phase.
What To Do
Vet visit for any garlic ingestion, even small amounts warrant bloodwork to assess RBC integrity. Blood transfusion may be needed in severe cases.
Notes
Garlic is present in many processed foods: hummus, pasta sauces, pre-seasoned meats, bouillon cubes, stock, baby food (used in some brands as a flavor enhancer), pizza, and ready meals. "Garlic-infused" olive oil contains sufficient allicin compounds to be a concern. See also: Onion (same mechanism, lower potency), Chives (same mechanism), Leeks, Shallots.
Sources
→ ASPCA Animal Poison Control Center — aspca.org
→ Merck Veterinary Manual — https://www.merckvetmanual.com/toxicology/food-hazards/garlic-and-onion-allium-spp-toxicosis-in-animals?query=garlic
→ Pet Poison Helpline — petpoisonhelpline.com/poison/garlic/