Is Chocolate Poisonous to dogs?

In April 2011, Pete Wedderburn wrote a piece on chocolate poisoning in small dogs for The Telegraph coming up to Easter. You can view the original piece here.

Everyone knows that fireworks are dangerous to pets. Yet this time of year – Easter – is a far riskier time for dogs for a simple reason: chocolate. The Veterinary Poisons Information Service recently published figures showed that chocolate was the most common poison to affect dogs in the UK with 1751 cases reported in 2010.

A small dog can die after eating a single Easter egg. The chemical in chocolate that gives humans a pleasant buzz – theobromine – has a highly toxic effect on dogs. A small chocolate feast that would be a pleasant indulgence for a human can kill a dog. Half a small bar of dark chocolate – around 50g (2 ounces) –  is enough to end the life of a little terrier. Milk chocolate is less dangerous, needing twice as much for the same effect.

Small dogs are much more at risk. Like most poisons, the effect is dose-dependent, so a 40kg Labrador would need to eat eight times as much chocolate as a 5kg terrier to be affected.

This is not just some theoretical risk. As a vet in practice, I see dogs dying of chocolate poisoning every year. If animals are rushed to the vet within an hour of eating the chocolate, there’s a good chance that they can be saved. Drugs can be given to induce vomiting, emptying the stomach before the chocolate has had time to be absorbed. If treatment is delayed, and the poison has been absorbed into the dog’s bloodstream, there’s sometimes little that can be done to help.

The signs of poisoning start within six hours of the chocolate being eaten, reaching a peak at around twelve hours, and continuing for another 24 to 48 hours. During this time, the chocolate toxins wreak havoc with the function of the heart and brain. Despite the best veterinary care, many patients don’t survive.

The signs of poisoning start with restlessness, vomiting and diarrhoea, with tremors, convulsions and heart failure following soon after. It’s a desperately worrying time for owners: their beloved pets are left in intensive care at the vets, and it’s a matter of waiting, hoping and praying. Some dogs survive; many don’t.

The big risk, contrary to popular perception, is not dogs being given occasional chocolate treats by pampering owners. All of the crises that I’ve seen have involved dogs discovering stashes of chocolate. A box of chocolates is left on a table, or an Easter egg on a sideboard. The dog sniffs out the chocolate, tears the wrapping off and scoffs the whole lot within minutes. Most humans feel full after eating half a dozen chocolates. Dogs have no such “off” switch; they just keep eating the chocolate until every last one has been consumed.

The key to saving a dog’s life in this situation is speed. Any dog that’s eaten more than a square or two of chocolate needs to be rushed to the vet, so that their stomach can be emptied before the chocolate toxins have been absorbed into the bloodstream. Phone your vet at once, whatever the time of day or night. Get your animal treated as soon as possible, whatever it takes.

Dogs die unnecessarily every Easter. Don’t let your pet be one of them.

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