Mild symptoms at 20 mg/kg theobromine, severe at 40+ mg/kg
If your dog ate chocolate, call your vet or ASPCA Poison Control (888-426-4435) immediately.
Theobromine and caffeine in chocolate are toxic to dogs because they metabolize these compounds much more slowly than humans (half-life: 17.5 hours in dogs vs 6 hours in humans). Toxicity levels: mild symptoms at 20 mg/kg (vomiting, diarrhea), moderate at 40 mg/kg (hyperactivity, tachycardia), severe at 60+ mg/kg (seizures, cardiac arrest). Theobromine content: white chocolate 0.9 mg/g, milk chocolate 1.5 mg/g, dark chocolate 5.3 mg/g, baker's chocolate 14 mg/g, cocoa powder 28 mg/g. A 30-lb dog eating 2 oz of baker's chocolate ingests ≈58 mg/kg — a veterinary emergency. Induce vomiting within 2 hours if possible. Treatment: activated charcoal, IV fluids, anti-seizure medication.