If your dog has eaten chocolate, this is a potential emergency. The danger depends on the type of chocolate, the amount eaten, and your dog's weight. Dark chocolate and cocoa powder are far more toxic than milk chocolate. Do not wait for symptoms—call your vet or the Animal PoisonLine (01202 509000) immediately.
Why Chocolate Is Toxic to Dogs
Chocolate contains two toxic compounds: theobromine and caffeine. Both are methylxanthines that dogs metabolise far more slowly than humans—a dog can take up to 17.5 hours to clear theobromine from its bloodstream, compared to just 3 hours in humans. This means even modest amounts can accumulate to dangerous levels.
Theobromine is the primary concern. It attacks the central nervous system, the cardiovascular system, and the respiratory system. Caffeine compounds the problem by increasing heart rate and blood pressure.
Chocolate Type Matters
The danger level varies dramatically by chocolate type:
- Dark chocolate and cocoa powder — Most dangerous. Dark chocolate contains 12–26mg of theobromine per gram, whilst cocoa powder contains 12–26mg per gram. As little as 20mg per kilogram of body weight can cause mild symptoms; 40–50mg/kg can cause serious toxicity; and 60mg/kg and above is life-threatening.
- Milk chocolate — Less concentrated at 0.5–3mg per gram. A typical 100g milk chocolate bar contains 50–150mg of theobromine total. This is usually only dangerous to very small dogs or if large amounts are consumed.
- White chocolate — Contains no theobromine whatsoever, though it is high in sugar and fat, which can cause other problems.
- Chocolate baking powder and cocoa powder — Extremely concentrated, often more dangerous than dark chocolate.
Calculating Chocolate Toxicity
To assess risk, calculate the dose per kilogram of your dog's body weight:
Dose (mg/kg) = Total theobromine content (mg) ÷ Dog's weight (kg)
Theobromine content guide:
- Dark chocolate (70%): 45mg per 28g square
- Milk chocolate: 6mg per 28g square
- Cocoa powder: 12–26mg per gram
- White chocolate: 0mg (not toxic, but high in fat and sugar)
Toxicity levels:
- Under 20mg/kg: Mild symptoms (vomiting, mild diarrhoea, restlessness)
- 20–40mg/kg: Moderate symptoms (vomiting, diarrhoea, tremors, rapid heart rate)
- 40–60mg/kg: Severe symptoms (seizures, heart arrhythmias, potential death)
- Over 60mg/kg: Life-threatening emergency
Example Scenarios
- A 5kg Chihuahua eats a 30g square of dark chocolate (high-cocoa): ~360mg theobromine ÷ 5kg = 72mg/kg. This is life-threatening.
- A 25kg Cocker Spaniel eats the same chocolate: 360mg ÷ 25kg = 14.4mg/kg. This may cause mild symptoms.
- A 25kg dog eats 100g of milk chocolate: ~75mg ÷ 25kg = 3mg/kg. This is likely safe, though monitoring is wise.
Symptoms of Chocolate Poisoning
Symptoms depend on the dose and typically appear within 6–12 hours:
- Vomiting and diarrhoea
- Restlessness, hyperactivity, or tremors
- Rapid or irregular heartbeat
- Excessive panting
- Muscle twitching or shaking
- Seizures (in severe cases)
- Collapse or loss of consciousness
In some cases, the first sign of a problem is a cardiac arrhythmia that only a vet can detect with a stethoscope or ECG. Never assume your dog is fine just because they are not visibly sick.
Even if your dog seems fine immediately after eating chocolate, contact your vet or the Animal PoisonLine (01202 509000) right away. Early treatment significantly improves outcomes. Do not wait for symptoms to develop.
What to Do If Your Dog Eats Chocolate
Immediate steps:
- Note the type and amount of chocolate (or find the packaging to confirm)
- Weigh your dog (or use a recent weight)
- Call your vet or the Animal PoisonLine (01202 509000) immediately — do not wait
- Have the following information ready:
- Type of chocolate (dark, milk, cocoa powder, etc.)
- Approximate amount in grams
- Time of ingestion
- Your dog's weight
- Follow your vet's instructions. They may recommend:
- Induced vomiting (within 1–2 hours of ingestion)
- Activated charcoal to absorb theobromine
- Monitoring at home or admission for observation
- Heart monitoring via ECG
- Supportive care (intravenous fluids, medications)
The SafeBowl app includes a chocolate toxicity calculator that instantly tells you the risk level based on chocolate type, amount, and your dog's weight. You can also use this to double-check your calculation before calling the vet.
Prevention
Keep all chocolate, cocoa powder, and chocolate-containing foods out of reach:
- Store chocolate in cupboards, not on counters or tables
- Be especially vigilant at Christmas, Easter, and other holidays when chocolate is abundant
- Check ingredient labels on baked goods, desserts, and breakfast cereals
- Educate children and visitors not to share chocolate with your dog
- Be aware of chocolate-covered items like chocolate-covered berries or nuts in holiday gift baskets
SafeBowl checks any food in seconds — personalised to your dog's breed, weight, and allergies. Download SafeBowl free.