Why chocolate is dangerous for dogs
Chocolate contains theobromine and a little caffeine, two stimulants that dogs eliminate much more slowly than people do. They overexcite the nervous system and the heart. The risk depends on three things: the type of chocolate, how much was eaten and the dog’s weight. Dark and baking chocolate are far more dangerous than milk chocolate, and white chocolate contains almost none.
If your dog ate chocolate, call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 (a consultation fee may apply). This calculator gives an estimate to help you describe the situation; it is not a diagnosis.
How the dose is calculated
- Theobromine swallowed (mg) = grams of chocolate × theobromine per gram
- Dose (mg/kg) = theobromine ÷ dog’s weight in kg
Typical theobromine content, in mg per gram: white chocolate about 0.01, milk chocolate about 2, semisweet and 50 to 69% dark about 5.5, 70 to 85% dark about 8, unsweetened baking chocolate about 14 and cocoa powder about 20. Brands vary, so the result is an approximation.
Usual thresholds
- Around 20 mg/kg: mild signs such as vomiting, diarrhea, thirst and restlessness.
- 40 to 50 mg/kg: heart effects such as a racing or irregular heartbeat.
- 60 mg/kg and above: tremors and seizures; this is an emergency.
Sensitive, old or heart-diseased dogs can react at lower doses, and caffeine adds to the effect.
Worked example: a 30-lb dog and a dark chocolate bar
A 30-lb dog (13.6 kg) eats 2 oz (57 g) of 70% dark chocolate.
- Theobromine: 57 × 8 = 454 mg.
- Dose: 454 ÷ 13.6 = 33 mg/kg, above the threshold for mild to moderate signs.
- For this dog, mild signs start around 1.2 oz of this chocolate, and the severe threshold is around 2.4 oz.
The same dog would need about 4.8 oz of milk chocolate to reach 20 mg/kg, which shows how much the type matters.
What to do
- Estimate what was eaten. Keep the wrapper: the cocoa percentage and weight help the vet.
- Call right away, even if your dog seems fine. Signs often start 6 to 12 hours after eating and can last a day or more.
- Do not induce vomiting at home unless a vet tells you to. A vet can do it safely within the first hours and may give activated charcoal and fluids.
- Watch for vomiting, panting, restlessness, a fast heartbeat, trembling or collapse, and go to an emergency clinic if they appear.
Prevention
Keep chocolate, cocoa powder, brownies and cocoa bean mulch out of reach, especially around holidays such as Halloween, Christmas, Valentine’s Day and Easter, when cases rise sharply.