Garlic — Food safety facts
Do not feed · Cats · full breakdown on the linked food page
Toxic. Damages red blood cells (hemolytic anemia), often days later. Powdered garlic is concentrated — worse by weight.
Short answer
Garlic is highly toxic to cats, and even a single small piece can be dangerous. It damages red blood cells, leading to a condition called hemolytic anemia, which often does not show symptoms like weakness, pale gums, or rapid breathing until several days after ingestion. Because the effects are delayed and serious, you should contact your veterinarian or the ASPCA Animal Poison Control Center at 888-426-4435 immediately if your cat has eaten any garlic, regardless of the amount. Do not attempt any home treatments.