Dark chocolate
ToxicDark and semisweet chocolate is the most dangerous everyday chocolate, carrying 5.3-5.6 mg of methylxanthines per gram. Anything above 20 mg/kg of body weight is an emergency.
This food guide has not been reviewed by a veterinarian. It summarises general information from sources and should not be used to decide whether a food is suitable for an individual dog or to assess an emergency.
Check before feeding
Do not offer as a treat
There is no recommended treat portion for this hazardous item. If swallowed, contact a vet with the amount, time and product details. Do not induce vomiting yourself.
Signs and health concerns
This list includes both observable signs and conditions identified through examination or testing. It cannot establish the cause or whether an exposure is safe.
- Vomiting
- Diarrhoea
- Increased thirst
- Restlessness
- Fast heartbeat
- Irregular heartbeat
- Tremors
- Seizures
More about this food
The toxins in chocolate are methylxanthines: theobromine and caffeine. They block adenosine receptors, inhibit phosphodiesterase and drive catecholamine release, which is why a poisoned dog looks wired rather than sleepy. Dogs metabolize theobromine slowly, so the half-life is long and signs drag on.
Do the math rather than guessing. Dark and semisweet chocolate contains 5.3-5.6 mg of methylxanthines per gram, or 150-160 mg per ounce. Multiply ounces by 155, divide by body weight in kilograms. The thresholds: mild GI signs from 20 mg/kg and up, which is already the point to call for help; cardiotoxicity at 40-50 mg/kg; seizures at 60 mg/kg and above. The LD50 for theobromine and caffeine is 100-200 mg/kg, which works out to roughly 62 g of chocolate per kg of body weight as a potentially lethal amount.
A worked case: a 22 lb (10 kg) dog eats a 100 g dark bar. 100 x 5.5 = 550 mg, divided by 10 kg = 55 mg/kg, squarely cardiotoxic and near the seizure threshold. Baking chocolate at 15.5 mg/g and cocoa powder at 28.5 mg/g are three to five times worse again -- 40 g of cocoa powder in that same dog is about 114 mg/kg, inside the LD50 range. In US homes the classic disasters are Halloween and Easter candy bowls, chocolate chips and baker's squares left on a counter, cocoa powder in the baking cabinet, and brownies.
Signs usually begin at 6-12 hours and can persist up to 72 hours: vomiting, diarrhea, increased thirst and urination, restlessness and hyperactivity, tachycardia, arrhythmias, hypertension, tremors, hyperthermia, and in severe cases seizures and coma.
Call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 (fee applies) with the product type, cacao percentage, weight eaten and time. Keep the wrapper. Do not induce vomiting at home; decontamination, repeated activated charcoal, fluids and ECG monitoring are veterinary decisions.
Frequently asked questions
- How much dark chocolate is toxic for a 20 lb dog?
- A 20 lb dog is about 9 kg, so 20 mg/kg is reached at roughly 33 g (a bit over one ounce) of dark chocolate at 5.5 mg/g. That is the emergency threshold, and 40-50 mg/kg -- around 75 g -- is the cardiotoxic band.
- Is baking chocolate or cocoa powder worse than a dark chocolate bar?
- Much worse. Baking chocolate runs 15.5 mg/g and cocoa powder 28.5 mg/g against 5.3-5.6 mg/g for dark chocolate. Forty grams of cocoa powder in a 10 kg dog is about 114 mg/kg, which falls inside the 100-200 mg/kg LD50 range.
- He ate it two hours ago and looks fine. Can I wait and see?
- No. Signs typically start at 6-12 hours and can last up to 72 hours because dogs clear theobromine slowly, so a normal dog at two hours means nothing. If the math puts the dose over 20 mg/kg, call now.