Yes, you’ve heard it so many times: chocolate is toxic to dogs. With the sweetest holiday of the year on the horizon, let’s look at why, though rarely fatal, ingesting chocolate can result in significant illness. Chocolate contains a chemical called theobromine, as well as caffeine. Both chemicals are used medicinally as a diuretic, heart stimulant, blood vessel dilator, and a smooth muscle relaxant. Dogs cannot metabolize theobromine and caffeine as well as people can, making them more sensitive to its effects.

The darker and more bitter the chocolate, the more dangerous it is to dogs.

The darker and more bitter the chocolate, the more dangerous it is to dogs. Baking chocolate and gourmet dark chocolate are highly concentrated; Common milk chocolate less so and white chocolate rarely poses any threat. However, even if the amount ingested is not a toxicity concern, dogs can still become ill from the fat and sugar in chocolate, including pancreatitis. 

To put this in perspective, a medium-sized dog weighing 50 pounds would only need to eat 1 ounce of baker’s chocolate, or 9 ounces of milk chocolate, to potentially show signs of poisoning. For many dogs, ingesting small amounts of milk chocolate is not harmful. 

Signs & Symptoms

The most common clinical signs of chocolate poisoning are vomiting, diarrhea, increased thirst, panting or restlessness, excessive urination, and racing heart rate. In severe cases, symptoms can include muscle tremors, seizures, and heart failure. When in doubt, immediate treatment by your veterinarian is recommended if a poisonous amount of chocolate is ingested as clinical signs of chocolate poisoning can take several hours to develop. 

Signs due to large exposures can last for days due to the long half-life of theobromine. This means that it remains in the bloodstream for a longer period. Theobromine can also be reabsorbed from the bladder, so intravenous fluids and frequent walks to encourage urination may be necessary. 

If treated early, decontamination including inducing vomiting and administering activated charcoal to prevent absorption of theobromine into the body may be all that is necessary. 

It is very common to provide supportive treatments such as intravenous fluid therapy to help stabilize a dog and promote theobromine excretion. All dogs ingesting a toxic amount of chocolate should be closely monitored for any signs of agitation, vomiting, diarrhea, nervousness, irregular heart rhythm, and high blood pressure. Medication to treat restlessness and other signs may also be necessary. 

Diarrhea & Upset Stomach

If your dog has not eaten enough chocolate to become toxic, but does show signs of diarrhea or upset stomach, a conservative treatment is to withhold all food for 12-24 hours or feed small amounts of an easily digested diet at more frequent intervals. Water should be offered at all times. The recommended diet is often a veterinary prescribed diet designed to be easy to digest, while also containing ingredients such as prebiotic fiber that helps the intestinal tract recover from what triggered the diarrhea. A home-cooked bland diet may also be recommended that contains a combination of cooked rice or pasta and boiled chicken. This conservative medical approach allows the body’s healing mechanisms to correct the problem. As the stools or appetite return to normal, you can gradually reintroduce your dog’s regular food by mixing it in with the special diet for several days.