Theobromine poisons dogs. Dark and baking chocolate are the most dangerous; a 50g dark bar can seriously poison a small dog. White chocolate is mostly a fat problem.
Equally toxic — cats are simply less often tempted. Any ingestion warrants a call.
Theobromine + caffeine; dogs metabolize theobromine slowly. Toxicity scales with cocoa % and body weight.
Restlessness, vomiting, diarrhea, tremors, racing heart, seizures — onset 6–12h.
Call the vet or poison control immediately with: type of chocolate, amount, your pet's weight, and when.
ASPCA Animal Poison Control: (888) 426-4435 · Pet Poison Helpline: (855) 764-7661 — 24/7, a fee may apply. Your own vet first when reachable.