Pets & Chocolate by Christine Attridge-Hardy

It is that time of year when chocolate plays a big role in many upcoming family holidays. Chocolate plays a big part in Valentine’s Day and Easter. If you and I have a hard time passing up a piece of chocolate! Think of hard it is for your dog to.

Chocolate contains a stimulant called theobromine (a bit like caffeine) that is poisonous to dogs. The amount of theobromide differs in the different types of chocolate (dark chocolate has the most in it).

What does theobromine do and what symptoms will I see?

Theobromide mainly affects the heart, central nervous system and kidneys. Symptoms will occur from 4-24 hours after your dog has eaten chocolate and will vary depending on the amount of chocolate (theobromine) your dog has eaten.

If your dog has eaten chocolate, you may see:

  • Vomiting (may include blood)
  • Diarrhoea
  • Restlessness and hyperactivity
  • Rapid breathing
  • Muscle tension, incoordination
  • Increased heart rate
  • Seizures

How much chocolate is too much for my dog?

Theobromine doses in the region of 100-150 mg/kg bodyweight are toxic to dogs.

Approximate amount of theobromine in 25grams of chocolate.

  • White chocolate contains minimal amounts of theobromine.
  • Milk chocolate contains 44-64 mg theobromine
  • Semi-sweet chocolate and sweet dark chocolate contains 150-160 mg theobromine
  • Unsweetened (baking) chocolate 390-450 mg theobromine
  • Dry cocoa powder 800 mg theobromine

This means that for a Labrador (around 30kg bodyweight) we would expect to see a fatal toxic reaction if they had eaten 1kg of milk chocolate, ½kg dark chocolate or 170grams of baking chocolate.

Signs of poisoning will be seen at lower levels of ingestion.  For example, a 30kg dog that has eaten 200g milk chocolate is likely to have a digestive upset (vomiting and diarrhoea).  If they had eaten 500g milk chocolate, it is likely that cardiovascular problems will be seen (increased heart rate) and if they had eaten 750g milk chocolate they may develop seizures.

It can be hard to tell exactly how much your dog may have eaten and the amount of caffeine and theobromine in chocolate will vary due to growing conditions, cocoa bean sources and variety. It’s always best to err on the side of caution and contact your vet for advice if you are at all concerned.

What should I do if my dog has eaten chocolate?

Treatment may be needed if your dog eats any chocolate so please contact your vet as soon as possible. Letting your vet know if you can how much chocolate your dog has eaten, what type of chocolate it was (wrappers can be very helpful) and when your dog ate the chocolate.  This will enable them to work out whether your dog has eaten a toxic dose or not and what treatment your dog is likely to need.

Treatment

There is no antidote to theobromine. In most cases your vet will make your dog vomit.  They may wash out the stomach and feed activated charcoal which will absorb any theobromine left in the intestine. Other treatments will depend on the signs your dog is showing.  They may need intravenous fluids (a drip), medication to control heart rate, blood pressure and seizure activity.

With prompt intervention and treatment even in dogs that have eaten large amounts of chocolate the prognosis for a poisoned dog is usually good.