If a dog eats chocolate, it can suffer from symptoms like vomiting, diarrhea, rapid breathing, and an abnormally high heart rate. The toxic compounds in chocolate stimulate the canine nervous system and can cause muscle tremors, seizures, or severe heart issues in heavy amounts. The severity of the reaction depends on the weight of the dog and the type of chocolate consumed. Dark chocolate and cocoa powder present the greatest danger to a dog health. Quick veterinary intervention is crucial to prevent serious medical complications.