How Much Chocolate Is Dangerous for a Dog?

Any chocolate can poison a dog, and dark chocolate and baking chocolate are the worst. How sick a dog gets depends on the type of chocolate, how much it ate and how much it weighs. If your dog has eaten some, call a vet now. Don't wait to see if symptoms appear.

Why chocolate is toxic

Chocolate contains theobromine and caffeine. Both are methylxanthines, and theobromine makes up most of it. Dogs clear theobromine slowly: half of it is still in the body about 17 hours after the dog ate it, so the effects last. Caffeine clears faster, with a half-life of about 4.5 hours.

How much is in different chocolates

The more cocoa, the more risk. These are the combined methylxanthine amounts, from the Merck Veterinary Manual:

| Type | mg per gram | mg per ounce | |---|---|---| | Cocoa powder | 28.5 | 807 | | Baking chocolate (unsweetened) | 15.5 | 440 | | Dark chocolate (semisweet) | 5.3 to 5.6 | 150 to 160 | | Milk chocolate | 2.3 | 64 | | White chocolate | 0.04 | 1.1 |

White chocolate has almost none, but its fat and sugar can still upset the stomach or trigger pancreatitis.

How much is too much

What matters is the dose per kilogram of body weight:

• About 20 mg per kg: mild signs such as vomiting, diarrhoea and extra thirst
• 40 to 50 mg per kg: effects on the heart
• 60 mg per kg or more: seizures
• 100 to 200 mg per kg: this is the dose that kills half of dogs in studies, and it can be fatal

Take a 10 kg dog. At 20 mg per kg that's 200 mg, which is about 13 g of baking chocolate, 37 g of dark chocolate or 87 g of milk chocolate. A dog that's smaller than this reaches the same dose on less. Treat these numbers as a rough guide, not a safe limit. Individual dogs react differently, and bars vary in cocoa content, so check the label.

Symptoms

Signs usually start 6 to 12 hours after the dog eats the chocolate and can last up to 72 hours in severe cases.

• Early: vomiting, diarrhoea, thirst, restlessness, passing more urine
• Moderate: fast heartbeat, panting, raised temperature, abnormal heart rhythm
• Severe: muscle tremors, seizures, collapse

What to do if your dog eats chocolate

1. Note the time, the type of chocolate and roughly how much. Keep the wrapper.
2. Know your dog's weight.
3. Call a vet straight away. During opening hours (Monday, Thursday and Friday 10:00 to 16:00, and Tuesday and Wednesday 09:00 to 17:00) you can call MyPeterinarian. Outside those hours, contact an emergency vet clinic.
4. Don't make your dog vomit at home unless a vet tells you to. Done wrongly, it can cause harm.

Treatment at the vet

The vet works out the dose from the type, amount and weight, then decides what's needed. Treatment can include:

• Making the dog vomit, ideally within about 2 hours of eating the chocolate
• Activated charcoal to limit what the gut absorbs, in cases of a large dose
• Fluids through a drip
• Heart monitoring, and medicine for an abnormal heart rhythm
• Medicine to control tremors and seizures
• Anti-nausea medicine

Outcome depends on the dose and on how soon treatment starts.

Prevention

• Keep chocolate in closed cupboards or on high shelves, and don't leave it in bags on the floor.
• Tell children and guests never to share chocolate with the dog.
• Take extra care at Easter, Christmas and other times when there are boxes and wrapped sweets around. Dogs smell residue on wrappers, so bin them where the dog can't reach.
• Reward your dog with dog treats, play or praise.

For questions about poisons or your dog's health, see our veterinary service or contact the clinic.