Call your vet or a pet poison line now
If your dog has eaten chocolate, phone first and calculate second. A vet can often make your dog vomit safely if it is caught early, and they will tell you if that is needed.
- US: ASPCA Animal Poison Control, (888) 426-4435; Pet Poison Helpline, (855) 764-7661
- UK: Animal PoisonLine, 01202 509 000
- Anywhere: your own vet or the nearest emergency vet
These lines charge a consultation fee. Have the wrapper, your dog’s weight and the time it ate the chocolate ready.
How to use the chocolate calculator
- Enter your dog’s weight.
- Choose the type of chocolate. If you are not sure, choose the darker option.
- Enter the amount eaten, from the wrapper. If you are not sure, enter the most it could have been.
- Tell your vet the result in mg/kg, along with the type and time.
The formula
Chocolate is dangerous because of theobromine and caffeine (methylxanthines). The Merck Veterinary Manual lists how much is in each type:
| Chocolate | mg per oz | mg per g |
|---|---|---|
| White chocolate | 1.1 | 0.04 |
| Milk chocolate | 64 | 2.3 |
| Dark or semisweet | 150–160 | 5.3–5.6 |
| Cocoa bean hull mulch | 255 | 9 |
| Unsweetened baking chocolate | 440 | 15.5 |
| Dry cocoa powder | 807 | 28.5 |
Dose (mg/kg) = ounces eaten × mg per oz ÷ dog’s weight in kg. For dark chocolate the calculator uses 160 mg per oz, the top of Merck’s range, to stay on the safe side.
Merck’s levels: mild signs (vomiting, diarrhoea, thirst) may occur from 20 mg/kg, heart effects at 40–50 mg/kg and seizures at 60 mg/kg or more. Merck gives the reported lethal dose (LD50) as 100–200 mg/kg, but notes that severe signs and death can occur at lower doses and that dogs vary.
Signs to tell your vet about
Vomiting, diarrhoea, drinking a lot, restlessness, panting, a racing heart, shaking, and in severe cases seizures. Do not wait for them.
Sources
- Merck Veterinary Manual (professional version): Chocolate Toxicosis in Animals, and table “Methylxanthine Content of Various Types of Chocolate”.
- ASPCA Animal Poison Control; Pet Poison Helpline; Animal PoisonLine (Veterinary Poisons Information Service, UK).
Frequently asked questions
How much chocolate can kill a dog?
It depends on the type of chocolate and the dog’s weight. The Merck Veterinary Manual says about 1 oz of milk chocolate per lb of body weight (62 g/kg) is potentially lethal, and that severe signs and death can happen at much lower doses. Dark and baking chocolate are far stronger. Call your vet or a pet poison line straight away.
How much chocolate is toxic to dogs by weight?
Merck reports mild signs (vomiting, diarrhoea, thirst) from about 20 mg of theobromine and caffeine per kg of body weight, heart effects at 40–50 mg/kg and seizures at 60 mg/kg or more. For a 20 lb (9 kg) dog, 20 mg/kg is about 2.8 oz (80 g) of milk chocolate but only about 1.1 oz (32 g) of dark chocolate.
My dog ate chocolate, what should I do?
Call your vet or a pet poison line now, even if your dog seems fine. Have ready the type of chocolate, how much (the wrapper helps) and when. In the US: ASPCA Animal Poison Control (888) 426-4435 or Pet Poison Helpline (855) 764-7661; in the UK: Animal PoisonLine 01202 509 000. These services charge a fee. Do not make your dog sick unless a vet tells you to.
Is dark chocolate worse than milk chocolate for dogs?
Yes, much worse. Merck lists about 64 mg of theobromine and caffeine per oz in milk chocolate, 150–160 mg in dark or semisweet, 440 mg in unsweetened baking chocolate and 807 mg in dry cocoa powder. White chocolate has very little, about 1 mg per oz, though its fat and sugar can still upset a stomach.
How long after eating chocolate will a dog get sick?
Signs can take hours to appear, and they can last a day or more because theobromine leaves a dog’s body slowly: Merck gives its half-life in dogs as about 17.5 hours. That is why you should call for advice straight away instead of waiting for symptoms.