My Dog Ate Chocolate: How Worried Should I Be?

Chocolate poisoning is real but the panic is often out of proportion to the dose. The toxic compound is theobromine, which dogs clear very slowly. Whether it matters depends on three things: the type of chocolate, how much, and how big your dog is.

Type matters most

White chocolate contains almost no theobromine and is mainly a fat and sugar problem. Milk chocolate contains a moderate amount. Dark chocolate contains several times more, and cocoa powder and baking chocolate are the most concentrated of all. A Labrador that ate a fun-size milk chocolate is a very different situation from a Yorkie that ate a slab of 70 percent dark.

The rough picture

Mild signs can start at relatively low doses of dark chocolate in a small dog, while a large dog may eat a whole milk chocolate bar with nothing worse than an upset stomach. Rather than doing arithmetic while worried, phone your vet with three facts: your dog's weight, the type of chocolate, and roughly how much. They will tell you in thirty seconds whether to come in.

What to watch for

Restlessness and hyperactivity, excessive thirst and urination, vomiting and diarrhoea, a racing heart, muscle tremors, and in severe cases seizures. Signs typically start within two to four hours and can last a long time because dogs eliminate theobromine so slowly.

What to do

Work out what was eaten and keep the wrapper.
Phone the vet rather than guessing. If treatment is needed, early decontamination is far more effective than waiting for signs.
Do not induce vomiting on your own initiative.
Remember that the fat and sugar can trigger pancreatitis in susceptible dogs even when the theobromine dose is low — a dog that is repeatedly vomiting and hunched needs to be seen regardless.

The one that is worse than chocolate

Xylitol, listed as birch sugar on some labels, is in sugar-free gum, some peanut butters, sweets and baked goods. It causes a catastrophic drop in blood sugar in dogs and liver failure, at tiny doses. If a dog eats anything sugar-free, treat it as more urgent than chocolate, not less.