What should I do if my cat ate chocolate?

Chocolate contains theobromine and caffeine, two methylxanthines that cats cannot metabolise efficiently. Even a small amount can cause vomiting, restlessness, a racing heart, tremors or seizures.

The danger depends on the type and amount of chocolate and your cat's weight. Unsweetened baking chocolate and dark chocolate contain the most theobromine, milk chocolate far less, and white chocolate almost none. As a rough guide, mild signs appear around 20 mg of theobromine per kilogram of body weight and seizures around 40 to 60 mg/kg, but never calculate this yourself instead of calling a professional. Signs usually start within 6 to 12 hours and can last up to 72 hours because theobromine is cleared slowly.

When you call, have ready: your cat's weight, the type of chocolate (brand and cocoa percentage if possible), an estimate of how much was eaten, and when it happened. Keep the wrapper and any leftovers. The vet may advise bringing the cat in for decontamination, activated charcoal, intravenous fluids and monitoring; there is no antidote, so treatment is supportive and works best when started early.

Do not give milk, oil, salt water or any home remedy — they do not help and can make things worse. If you cannot reach your own vet, call an emergency clinic or a 24-hour animal poison control service such as the ASPCA Animal Poison Control Center, and be prepared to pay a consultation fee. If your cat is already having seizures, struggling to breathe or collapsing, go straight to the nearest emergency hospital.