My dog ate chocolate: how much is dangerous?
Chocolate is dangerous because it contains theobromine and caffeine, and the risk depends on the type of chocolate and your dog's weight. The Merck Veterinary Manual says mild signs can appear at about 20 mg of these compounds per kg of body weight, heart problems at 40 to 50 mg/kg and seizures at 60 mg/kg or more; cocoa powder and baking chocolate are by far the most concentrated. If your dog has eaten chocolate, call your vet now and use the estimator below to give them the numbers.
Chocolate dose estimator
An estimate only, using average methylxanthine levels from the Merck Veterinary Manual. Real products vary, and some dogs react at lower doses. It does not replace a vet. In the US, the ASPCA Animal Poison Control Center is on (888) 426-4435.
What to do right now
- Work out what and how much. Find the wrapper. Note the type of chocolate (or the cocoa percentage), roughly how much is missing, and when it was eaten.
- Weigh your dog or use its last weight from the vet.
- Call your vet, an emergency vet or a pet poison line and give them those numbers. Do this even if your dog seems completely normal: Merck says signs usually appear 6 to 12 hours after eating.
- Do not try home remedies unless a vet tells you to. Merck notes vets may induce vomiting if the chocolate was eaten recently (for example within 2 hours) and the dog is still well, but this should be done under veterinary guidance.
Why chocolate is toxic to dogs
Chocolate is made from roasted cacao seeds, which contain two stimulants called methylxanthines: theobromine and caffeine. Theobromine is present at 3 to 10 times the concentration of caffeine, and both contribute to poisoning. They stimulate the nervous system and the heart. Dogs also clear theobromine slowly; Merck gives its half life in dogs as 17.5 hours, compared with 4.5 hours for caffeine, which helps explain why signs can last a long time.
Which chocolate is most dangerous?
| Type | Methylxanthines (Merck) | Relative risk |
|---|---|---|
| Cocoa powder | 28.5 mg/g (807 mg/oz) | Highest |
| Unsweetened baking chocolate | 15.5 mg/g (440 mg/oz) | Very high |
| Cocoa bean hull garden mulch | about 9 mg/g (255 mg/oz), though some mulches have it removed | High |
| Semisweet and sweet dark chocolate | 5.3 to 5.6 mg/g (150 to 160 mg/oz) | High |
| Milk chocolate | 2.3 mg/g (64 mg/oz) | Moderate |
| White chocolate | 0.04 mg/g (1.1 mg/oz) | Negligible stimulant, but fatty |
For bars labeled with a cocoa percentage, Merck's method is to multiply the percentage by the figure for unsweetened chocolate: a 70 percent bar has about 0.70 × 15.5 = roughly 10.9 mg per gram. The estimator above does the same.
A worked example
A 10 kg (22 lb) dog eats 50 g (about 1.8 oz) of milk chocolate. That is 50 × 2.3 = 115 mg of methylxanthines, or 11.5 mg per kg: below the level at which Merck says mild signs typically start, but still worth a call to the vet. If the same dog ate 50 g of 70 percent dark chocolate, the dose would be about 50 × 10.9 ÷ 10 = roughly 54 mg/kg, in the range where Merck says heart effects occur. That is an emergency. Merck also gives a rule of thumb that about 1 oz of milk chocolate per pound of body weight (62 g/kg) is potentially lethal.
Signs of chocolate poisoning
According to Merck, early signs include increased thirst, vomiting, diarrhea, a swollen belly and restlessness. These can progress to hyperactivity, increased urination, wobbliness, rigid muscles, tremors and seizures, along with a fast heart rate, abnormal heart rhythms, rapid breathing, high body temperature and, in severe cases, collapse or coma. In severe cases signs can last up to 72 hours. The high fat content of chocolate can also trigger pancreatitis in susceptible dogs.
How vets treat it
There is no simple test or antidote; diagnosis is based on what was eaten and the signs. Treatment may include making the dog vomit if it is caught early, medicines to control vomiting, tremors and heart rhythm, intravenous fluids, and monitoring of heart rhythm and temperature. The sooner a vet is involved, the more options there are.
Preventing it
- Keep chocolate, cocoa and baking supplies in closed cupboards, not on low tables or in bags on the floor.
- Be extra careful at holidays, when gifts, advent calendars and chocolate eggs are around; remind visitors and children not to share.
- Avoid cocoa bean hull mulch in gardens your dog uses.
- Check other foods for chocolate, coffee and xylitol in our Can dogs eat this? table.
Frequently asked questions
Can a small piece of chocolate kill a dog?
A small piece of milk chocolate is unlikely to be fatal for a medium or large dog, but the risk rises sharply with darker chocolate, cocoa powder and smaller dogs. Merck says mild signs can start at about 20 mg/kg, so always calculate the dose and call your vet.
How long after eating chocolate will a dog get sick?
The Merck Veterinary Manual says signs usually appear 6 to 12 hours after ingestion, and in severe cases can last up to 72 hours.
Is white chocolate safe for dogs?
White chocolate contains only negligible amounts of theobromine, so it is very unlikely to cause stimulant poisoning, but its fat and sugar can still upset the stomach and may trigger pancreatitis in susceptible dogs.
Sources
- Chocolate Toxicosis in Animals, Merck Veterinary Manual
- People Foods to Avoid Feeding Your Pets, ASPCA Animal Poison Control
General education only, not veterinary advice. If you are worried about your dog, contact your vet; in an emergency, contact an emergency vet straight away.