Why Is Onion Harmful for Pets?

Onions, whether raw, cooked, powdered, or in fried foods, contain N-propyl disulfide, a compound that damages red blood cells in pets and leads to hemolytic anemia. Symptoms include weakness, pale gums, rapid breathing, dark urine, vomiting, and collapse. Effects can appear 1 to 5 days after exposure. Dogs are most sensitive, but cats, horses, and even small amounts in baby food can trigger issues. Toxicity starts at 0.5% of body weight (one medium onion for a 20-pound dog). Keep onions out of reach, check ingredient labels on human foods, and seek vet care for suspected exposure.