Why is chocolate toxic?

Chocolate contains toxins: mainly methylxanthines but also theobromine and caffeine. Dogs and cats process these substances much more slowly than people, allowing them to accumulate and affect the gastrointestinal tract, heart and nervous system.

Risk depends on your pet’s weight, the type and amount of chocolate eaten, and the time since ingestion. Cocoa powder, baking chocolate and dark chocolate contain the highest concentrations. 

Milk chocolate contains less, while white chocolate contains very little theobromine but can still cause gastrointestinal upset or pancreatitis because it is high in fat and sugar.

What information should I collect?

Before contacting the veterinary team, gather the following where possible:

• Your pet’s current weight
• The type, brand and cocoa percentage of the chocolate
• The amount that may have been eaten, using the largest possible missing amount
• The approximate time of ingestion
• The packaging and ingredient list

Bring the packaging with you. Chocolate products may also contain other hazards such as xylitol, raisins, macadamia nuts, coffee or alcohol, and wrappers or foil may cause gastrointestinal obstruction.

What signs might I see?

Signs commonly begin within several hours, but onset and severity vary. Because theobromine is eliminated slowly, effects may persist for one to three days in more significant cases.

• Vomiting, diarrhoea, drooling or abdominal discomfort
• Increased thirst and urination
• Restlessness, agitation or hyperactivity
• A rapid heart rate, abnormal heart rhythm or high blood pressure
• Rapid breathing or increased body temperature
• Wobbliness, muscle tremors or seizures
• Weakness, collapse, coma or death in severe cases

High-fat chocolate products may also trigger pancreatitis, causing vomiting, reduced appetite and abdominal pain, sometimes after the initial toxicity risk has passed.

How is the risk assessed?

There is no single blood test that confirms chocolate poisoning. Your veterinarian estimates the methylxanthine dose using your pet’s weight and the chocolate type and amount, then considers the time since ingestion and any clinical signs.

When the amount is uncertain, the safest approach is to assume the largest possible amount was eaten. Dogs that appear normal after a potentially toxic ingestion may still benefit from early decontamination.

How is chocolate toxicosis treated?

There is no specific antidote. Treatment aims to remove chocolate before it is absorbed, reduce further absorption and support the heart, nervous system and hydration until the toxins are eliminated.

• Inducing vomiting when ingestion was recent and the patient is alert and neurologically normal
• Activated charcoal
• Intravenous fluids to support hydration
• Electrocardiogram and blood pressure monitoring
• Medication to control nausea, agitation, tremors, seizures or abnormal heart rhythms
• Temperature, electrolyte and blood glucose monitoring when indicated