Chocolate Toxicity in Dogs

Why chocolate is toxic to dogs

Chocolate contains theobromine and caffeine, two stimulants from the methylxanthine family. People clear them in a few hours. In dogs, theobromine has a half-life of about 17.5 hours, so it builds up and keeps working long after the chocolate is gone. These stimulants over-excite the heart, nervous system and muscles.

Symptoms of chocolate toxicity in dogs

• Early (within 6 to 12 hours): vomiting, diarrhea, excessive thirst, a bloated belly, restlessness
• Moderate: hyperactivity, panting, peeing a lot, a racing heart
• Severe: wobbly walking, muscle tremors, high body temperature, abnormal heart rhythms, seizures, collapse

Symptoms can last up to 72 hours in severe cases. A large fatty binge can also trigger pancreatitis a few days later.

How much chocolate is toxic?

According to the Merck Veterinary Manual, mild signs can appear at 20 mg of methylxanthines per kg of body weight. Heart effects appear at 40 to 50 mg/kg, and seizures at 60 mg/kg or more. Content varies hugely by type: cocoa powder has about 807 mg per ounce, baker's chocolate 440, semisweet and dark 150 to 160 (more for very high-cocoa bars), milk chocolate 64, and white chocolate almost none.

The quickest way to put that into numbers for your dog is the chocolate toxicity calculator.

How vets treat chocolate poisoning

1. Inducing vomiting if the chocolate was eaten in the last 1 to 2 hours and the dog has no symptoms yet.
2. Activated charcoal only in large doses, given carefully, because it can upset sodium levels.
3. IV fluids to support the heart and speed up excretion.
4. Medication to control vomiting, tremors, seizures and abnormal heart rhythms.
5. Monitoring, sometimes with a urinary catheter, because theobromine can be reabsorbed from the bladder.

With prompt treatment, most dogs recover fully within 24 to 72 hours.

Prevention tips

Store chocolate, baking cocoa and hot chocolate mix in closed cupboards. Watch out for Easter egg hunts, Advent calendars and gift boxes under the tree (dogs can smell them through the wrapping). Don't use cocoa bean shell mulch in gardens dogs can reach.