Onions
DangerousOnions contain N-propyl disulfide which damages red blood cells in dogs.
Toxicity Level
8/10Why It's Dangerous
All forms of onions (raw, cooked, powder) are toxic. Garlic is also dangerous but less potent.
The Science
Thiosulphates (n-propyl disulfide)Onions, garlic, leeks, and chives belong to the Allium family. They contain organosulfur compounds, particularly n-propyl disulfide, which cause oxidative damage to red blood cells. This leads to the formation of Heinz bodies (denatured hemoglobin) on the red blood cell membrane, causing them to rupture. The result is hemolytic anemia — the dog's body destroys its own red blood cells faster than it can replace them. All forms are dangerous: raw, cooked, dried, powdered, or as part of a dish.
Sources
- •Journal of Veterinary Internal Medicine — Allium Species Toxicosis
- •ASPCA Animal Poison Control Center
- •Merck Veterinary Manual
Dosage & Thresholds
Toxicity in dogs occurs at approximately 15-30g of onion per kg of body weight. For a 10kg dog, that is roughly half a medium onion. However, repeated small exposures also accumulate and cause damage. Garlic is 3-5x more concentrated than onion and is toxic at around 5g/kg. Baby food, sauces, and soups often contain hidden onion or garlic powder.
Symptoms to Watch For
If your dog has ingested onions
Contact your veterinarian or an emergency animal poison hotline immediately. Do not induce vomiting unless instructed by a vet.
callFind Emergency Vet