Why?

Dogs metabolize theobromine and caffeine far more slowly than humans. While a person clears theobromine in a few hours, a dog's half-life for the compound is 18 hours, allowing it to accumulate to toxic concentrations. Theobromine acts as a stimulant and diuretic, affecting the cardiovascular and central nervous systems.

The toxicity is dose-dependent and chocolate-type-dependent. Dark chocolate and baking chocolate contain 8–16 times more theobromine per ounce than milk chocolate, making them far more dangerous per bite. White chocolate contains negligible theobromine but is still not a safe food due to its fat and sugar content.

Holiday seasons see the highest incidence of chocolate poisoning in dogs. Even "small amounts" of dark chocolate can be dangerous in small breeds — a single square of 70% dark chocolate can exceed the toxic threshold for a 10-lb dog.

How much is dangerous?

Theobromine content varies significantly: baking chocolate (~450mg/oz), dark chocolate (~150mg/oz), milk chocolate (~60mg/oz), white chocolate (~1mg/oz). The toxic threshold is approximately 20mg of theobromine per kg of body weight (mild signs) and 40mg/kg (severe signs). A 20-lb dog can experience serious toxicity from just 1 oz of dark chocolate.

What are the symptoms?

ONSET:Symptoms appear within 6–12 hours of ingestion. Cardiac and neurological signs peak at 12–36 hours.
  • vomiting
  • diarrhea
  • excessive thirst and urination
  • restlessness and hyperactivity
  • muscle tremors
  • seizures
  • rapid or irregular heart rate
  • collapse in severe cases

What should I do?

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Contact your vet or ASPCA Poison Control (+1 888-426-4435) with the chocolate type, quantity eaten, and your dog's weight — they can calculate the exact theobromine dose. Inducing vomiting is often recommended within 2 hours of ingestion. Hospitalization may be needed for monitoring and treatment.

Frequently asked questions.

Will my dog be okay if he ate a little bit of chocolate?

It depends on the chocolate type, the amount, and your dog's size — a small amount of milk chocolate may cause only mild GI upset in a large dog, while the same amount of dark chocolate could be dangerous for a small dog. Call your vet with the specifics so they can calculate the actual theobromine dose.

What if my dog ate chocolate and seems fine?

Signs can take 6–12 hours to appear. Call your vet with specifics (type and amount eaten, dog weight) so they can assess the exact risk.

Is white chocolate toxic to dogs?

White chocolate contains almost no theobromine, but the high fat content can cause pancreatitis. It is not safe, but the emergency level is lower than with dark chocolate.

Will one Malteser hurt my dog?

A single Malteser contains a small amount of milk chocolate — for most medium-to-large dogs this is unlikely to cause serious harm, but it can still pose a risk to small or toy breeds, and chocolate should never be given intentionally. If your dog ate more than one or two, contact your vet.

Will one Hershey Kiss hurt a dog?

One Hershey Kiss is milk chocolate in a small quantity, which is generally a low risk for a medium or large dog but can be more concerning for a small dog. Monitor for vomiting or diarrhea, and call your vet if your dog is small, ate more than one, or shows any symptoms.

Disclaimer: This information is for educational purposes only and does not constitute veterinary advice. Every dog is different. Always consult your veterinarian before making changes to your dog's diet or in the event of a potential poisoning emergency.