Why chocolate is toxic to dogs
Chocolate contains theobromine and caffeine, two stimulants called methylxanthines. Dogs break them down much more slowly than people, so they build up and overstimulate the heart and nervous system. The darker and more bitter the chocolate, the more theobromine it has: baking chocolate and cocoa powder are far more dangerous than milk chocolate, and white chocolate has almost none.
How the calculator works
| Chocolate | Theobromine + caffeine per oz |
|---|---|
| White chocolate | about 0.25 mg |
| Milk chocolate | about 64 mg |
| Semisweet and sweet dark chocolate | about 150-160 mg |
| Unsweetened baking chocolate | about 440-450 mg |
| Dry cocoa powder | about 800 mg |
We use the upper value for each type so the result errs on the safe side.
Toxic doses
| Dose | What can happen |
|---|---|
| Under 20 mg/kg | Usually no signs, sometimes an upset stomach |
| 20 mg/kg | Mild signs: vomiting, diarrhea, thirst, restlessness |
| 40-50 mg/kg | Heart effects: fast or irregular heartbeat |
| 60 mg/kg and up | Tremors, seizures, can be fatal |
Worked examples
- A 20 lb dog (9.1 kg) eats 2 oz of milk chocolate: 2 × 64 = 128 mg, or 14 mg/kg. Low risk, but watch for an upset stomach.
- The same dog eats 1 oz of baking chocolate: 450 mg, or 50 mg/kg. Serious: call a vet now.
- A 60 lb Labrador (27.2 kg) eats a 6 oz bag of semisweet chips: 960 mg, or 35 mg/kg. Mild to moderate: call a vet.
What to do if your dog ate chocolate
- Work out what and how much. Keep the wrapper: it shows the type and weight.
- Call your vet or a poison hotline with your dog's weight and the amount. They may ask you to come in so they can make your dog vomit safely, usually within 1 to 2 hours of eating.
- Do not give salt, hydrogen peroxide or other home remedies unless a vet tells you to.
- Watch for signs for 24 to 72 hours. They usually start 6 to 12 hours after eating and can last several days.
Also check the label for xylitol (sugar-free chocolate and candy), raisins and macadamia nuts, which are dangerous for dogs on their own. See the can dogs eat it checker for other foods.
Sources: Merck Veterinary Manual, "Chocolate Toxicosis in Animals" (methylxanthine content and toxic doses); ASPCA Animal Poison Control Center.
Frequently asked questions
How much chocolate can kill a dog?
Severe signs and death are possible from about 60 mg of theobromine and caffeine per kg. That is roughly 1 oz of baking chocolate per 7.5 kg (16 lb) of dog, or about 1 oz of milk chocolate per kg (2.2 lb).
My dog ate one chocolate chip cookie. Is that dangerous?
For most medium and large dogs, one cookie is a low dose and causes little more than an upset stomach. For a very small dog, or if the cookie had dark chocolate, raisins, macadamia nuts or xylitol, call your vet.
How long after eating chocolate will a dog get sick?
Signs usually start 6 to 12 hours after eating and can last up to 72 hours, because dogs clear theobromine slowly.
Is white chocolate toxic to dogs?
White chocolate has almost no theobromine, so poisoning is very unlikely. The fat and sugar can still cause vomiting, diarrhea or pancreatitis.
Should I make my dog throw up after eating chocolate?
Only if a vet or poison hotline tells you to. Vets can make a dog vomit safely with medicine; home methods like salt can be dangerous.
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Last updated October 2026.