My dog ate chocolate — what's the lethal dose and what symptoms should I watch for?

Quick answer

The compound 'theobromine' in chocolate is a toxin dogs can't properly metabolize. Symptoms like vomiting, diarrhea, rapid breathing, elevated heart rate, and seizures typically appear within 2–12 hours of ingestion. The higher the cocoa content (dark chocolate), the more dangerous even a small amount is. If your dog ate any amount, go to the vet immediately for treatment, which may include inducing vomiting.