How Much Chocolate is Toxic to Cats?

Cat sniffing chocolate

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People can eat chocolate, so why does a cat have a hard time with it? Chocolate is dangerous to cats because of the alkaloid theobromine, which can cause nausea, diarrhea, seizures, racing heartbeat, among more serious complications like a heart attack or death. This substance is a stimulant that is in the same family as caffeine.

Besides being smaller, an animal's digestive system is different than humans. It takes a much longer amount of time for a cat to metabolize theobromine in the system than a person. 

How Much Chocolate Is Too Much?

The amount of chocolate your cat can tolerate varies based on several factors. It depends on the type of chocolate, the size of the cat, and how much it has consumed. Take a look at a chocolate toxicity calculator for an estimate of how much chocolate may be dangerous for your cat. The toxicity levels are the same for cats and dogs.

For example, a toxic dose of theobromine and caffeine for pets is 100 to 200 milligrams for every 2.2 pounds (1 kilogram) that the animal weighs. However, some reports by the American Society for the Prevention of Cruelty to Animals have noted health problems at much lower doses, such as 20 milligrams.

So how does that translate for your cat? If you use the measure of 20 milligrams, which would be when symptoms may start appearing in your cat, then that means a 25-pound cat would need to consume about 4.5 ounces of milk chocolate to consume about 20 milligrams of theobromine. Some cats will not appear affected, but some may. This is a much more conservative toxic level calculation than the standard of 100 to 200 milligrams, but it is better to be safe than sorry.

Perhaps the easiest rule of thumb would be to think that one ounce of milk chocolate per pound of body weight is a potentially lethal dose in cats.

Types of Chocolate and Levels of Theobromine

Some chocolates are more toxic than others. The sweeter the chocolate, the lesser the theobromine level since theobromine is a bitter substance. Unsweetened baker's chocolate contains eight to 10 times more theobromine than milk chocolate. White chocolate has hardly any theobromine, so theobromine poisoning is highly unlikely if your pet consumes it.

How Big a Threat Is Chocolate for Cats?

Dogs are much more in danger than cats to get chocolate toxicity. Even though the toxicity level for a cat or dog is the same depending on weight, dogs have a sweet tooth and cats do not. So, while a cat may try some chocolate, it is less likely to continue eating it.

The bottom line is that a cat sneaking a couple M&M's or Hershey's Kisses should not have a problem, but it is not a good habit to get into. But, a chocoholic cat can be a problem.

Medical Treatment for Your Pet

A veterinarian's medical treatment for chocolate poisoning usually involves inducing vomiting within two hours of eating the chocolate. The doctor may also give the cat medications to control its heart rate.