Chocolate is poisonous for both dogs and cats. Cats are more sensitive to the toxic effects but because they tend to be less prone to scavenging we don’t see problems as commonly.
The problem with chocolate is a substance in it called theobromine which dogs and cats metabolise very slowly. It is in fact toxic for humans as well, but because we can metabolise it faster we don’t encounter the same problems as pets.
The amount of theobromine in chocolate varies depending on the amount of cocoa it has. For instance dark cooking chocolate might contain 70-80% cocoa whereas milk chocolate might only be 30-35%. As a result the darker and more refined the chocolate, the more toxic it is for pets.
Symptoms of toxicity vary depending on the amount ingested. Early signs include nausea and diarrhoea. More advanced symptoms include hyperactivity, muscle twitching, seizures, rapid heart rate and can lead to death. The symptoms will usually be seen 2-4 hours after ingestion. Unfortunately there is no antidote for the poisoning, we can only treat and control the symptoms and wait for the animal to recover which can take 12-72 hours depending on the severity of the signs.
As mentioned the toxic dose will vary depending on the type of chocolate ingested. It is important to note though, all dogs respond differently to the toxin (just like people have different sensitivities to caffeine, a similar stimulant to theobromine). This means some dogs are much more sensitive, as such it is safer to say that no amount of chocolate is safe for dogs.
If your dog does eat chocolate the best option is to call us immediately. We will help you decide how big the risk is to your pet, and in some circumstances may advise you how to make your dog vomit or to bring them straight in to the clinic for the appropriate treatment.