Why Dogs Can't Eat Chocolate

By: Dr. Dawn Ruben

The worst a Hershey bar can do to you is add an inch to your hips. But that same candy – even in relatively small amounts – can make a dog very sick. Make no mistake: For them, chocolate is poison. 

In addition to a high fat content, chocolate contains caffeine and theobromine, two different types of stimulants that affect the central nervous system and the heart muscle, as well as increasing the frequency of urination. 

Symptoms of Poisoning
If your 50-pound dog gets his paws on a single chocolate-chip cookie, it probably won't cause him serious problems. However, if he gobbles up more – a pan of brownies, say – he may develop vomiting or diarrhea. 

Once toxic levels are reached, the stimulants kick in, and this is when you really have to worry. Symptoms include: restlessness, hyperactivity, muscle twitching, increased urination and/or excessive panting. If your pet isn't treated, he could go into a seizure – possibly even die.

How Much Is Toxic?

The amount of chocolate that it takes to poison your pet depends on the type of chocolate he's eaten and his weight. White chocolate has the least amount of stimulants and baking chocolate or cocoa beans have the highest. Here is a list of the most common sources of chocolate and the amount that leads to toxicity:

·  White Chocolate. Mild signs of toxicity can occur when 45 ounces per pound of body weight is ingested. Severe toxicity occurs when 90 ounces per pound of body weight in ingested. This means that a 20-pound dog would need to ingest at least 55 pounds of white chocolate to cause nervous system signs. A 10-pound cat would need to ingest 27 pounds. Yes, that is twenty seven pounds! White chocolate has very little real chocolate in it. Therefore, the levels of caffeine and theobromine are very low. Tremendous amounts of white chocolate need to be ingested in order to cause toxic signs from chocolate. It is highly unlikely that white chocolate ingestion will result in the toxic neurologic signs but, the severe gastrointestinal effects from a high fat food develop with much less white chocolate ingestion.

·  Milk Chocolate. Mild signs of toxicity can occur when 0.7 ounces per pound of body weight is ingested. Severe signs occur when 2 ounces per pound of body weight is ingested. This means that a little less than one pound of milk chocolate can be toxic to the nervous system of a 20-pound dog. A 10-pound cat would need to ingest 1/2 pound.

·  Semi-Sweet Chocolate. Mild signs of toxicity can occur when 1/3 ounce per pound of body weight is ingested. Severe signs occur when 1 ounce per pound of body weight is ingested. This means that as little as 6 ounces of semi-sweet chocolate can be toxic to the nervous system of a 20-pound dog. A 10-pound cat would need to ingest 3 ounces.

·  Baking Chocolate. Mild signs of toxicity can occur when 0.1 ounce per pound of body weight is ingested. Severe signs occur when 0.3 ounce per pound of body weight is ingested. Two small one-ounce squares of baking chocolate can be toxic to a 20-pound dog. A 10-pound cat would need to ingest 1 ounce of baking chocolate. This type of chocolate has the highest concentration of caffeine and theobromine and very little needs to be ingested before signs of illness become apparent.

Even if your pet doesn't eat enough chocolate to induce toxicity, the candy's high fat content may cause him to vomit or have diarrhea at much smaller amounts than those shown. If that happens, watch him carefully. If his symptoms don't clear up within eight hours, call your veterinarian (if your pet is very small or young, call within four hours); aside from toxicity issues, you don't want the animal to dehydrate. Try to be as precise as you can about the type of chocolate the animal ate, how much he took and approximately when he ate it. 

The sooner you get help, the better off your pet will be. If the animal is showing signs of toxicity, he has a good prognosis if he's treated within four to six hours of ingestion. The effects of the chocolate can linger for 12 to 36 hours, though, so your pet may require hospitalization.