Why is chocolate so dangerous for dogs?

Posted on Sep 20, 2022      28

Cocoa, the key ingredient in chocolate, contains alkaloids that can have fatal effects on a dog’s body

That chocolate should not be given to dogs is common knowledge. The topic frequently comes up in conversations with owners, with degrees of harm ranging from “it will make them sick” to “it will literally turn them inside out and even kill them”. Interestingly, both are true, but not everyone knows why chocolate is so harmful. To understand the problem, we’re going to have to talk a little of uncomfortable bird language. Bear with me.

The harm that can cause a dog chocolate is not so much related to the caloric content of this product or excess carbohydrates, but to the peculiarities of our pets’ metabolism. Theobromine and caffeine alkaloids of the methylxanthines in cocoa beans are the major culprits: it is the psychoactive properties of these compounds that make us enjoy coffee so much, and why chocolate is so dangerous for dogs.

Besides chocolate, methylxanthines are found in many foods, including tea, coffee, and, of course, cocoa. People have been taking these stimulants for centuries without serious health consequences, even creating an entire culture of drinking them. Methylxanthines stimulate the heart rhythm and have a stimulating effect on the nervous and respiratory systems, contributing to an overall state of pleasant alertness.

But if a human can eat a chocolate bar and get a boost of energy, then the dog is more likely to go under the IV afterwards. How so? Well, the fact is that humans absorb methylxanthines easily. For example, the half-life of theobromine, the time to halve its concentration in the body, is only two to three hours. Given the diuretic effect of methylxanthines, these stimulants are eliminated from the body so quickly that they do not have time to cause any significant harm to humans.

In dogs, the half-life of theobromine is about 18 hours. A high concentration of this stimulant stays in the body nine times longer than in humans! The duration of exposure is precisely what determines the harm of chocolate, because for almost a day after consuming it, the dog’s body remains under the influence of psychoactive substances that force the heart and nervous system to work intensively, which consequently contributes to their sped up wear and tear.


No, don’t be alarmed: certainly, most dogs won’t be torn apart by a single chocolate candy. Scientists have found that the minimum toxic dose of theobromine for dogs is 92 to 136 mg per kg of animal weight, while a dose of 228 to 456 mg per kg can be fatal. How much is that in familiar “bar” terms, given that chocolate can vary?

Bitter, or as it is also called, dark chocolate, contains much more cocoa than milk or white varieties. This bar comprises 100% real Colombian cocoa.

Logic dictates that higher cocoa content means more theobromine and caffeine in the product, which means dark, bitter chocolate must be much more dangerous for dogs than milk or white chocolate. Nutritionists confirm there is indeed a difference between the varieties in the content of psychoactive substances. The amount of theobromine in chocolate varies:

  • Dark chocolate: up to 1,560 mg of theobromine per 100 grams, depending on the variety;
  • Baking chocolate: 1370 mg theobromine per 100 g;
  • Semi-sweet chocolate chips: 530 mg theobromine per 100 g;
  • Milk chocolate: 155 mg theobromine per 100 g;
  • White chocolate: 0.88 mg theobromine per 100 g.

By performing simple calculations, you can learn that even for the Chihuahua, the lethal dose is about 100 grams of good bitter chocolate. The figure is not so terrible, but there is no reason for jokes: it is necessary to understand that there are other factors besides the dosage, including the state of the cardiovascular system or the sensitivity of the concrete dog to these compounds.


Clearly, eating chocolate rarely has fatal consequences. If the dog is healthy and has no individual intolerance to any of the ingredients in the chocolate, the case will most likely be limited to vomiting or diarrhea with a slightly agitated state and a smirking look from the owner, saying, “you will know how to steal sweets”.

Chocolate poisoning in dogs is often accompanied by palpitations and heavy, rapid breathing.

However, there are dogs in whom even small amounts of this treat can cause a very acute reaction. The unpleasant thing about chocolate poisoning is that the list of symptoms is too wide for “normal” poisoning. If the owner is unaware of what has happened, it may be difficult for the veterinarian to determine the true cause of the dog’s ailment. What adds to the difficulty is that the first symptoms may not appear for several hours but may take almost a day after eating the chocolate.

Since theobromine primarily affects the central nervous, cardiovascular and respiratory systems, and also has a diuretic effect, chocolate poisoning is most often accompanied by the following symptoms:

  • Vomiting;
  • Diarrhea;
  • Rapid heartbeat;
  • Restlessness;
  • Hyperactivity;
  • Frequent urination;
  • Muscle spasms;
  • Seizures and other neurological signs.

Symptoms of chocolate poisoning in dogs may appear about two hours after consuming the product. The first signs include vomiting, including vomiting blood, and abnormal thirst. If a dog has eaten a lot of chocolate, excitability is likely to increase after a while, with tachycardia, rapid breathing and muscle twitching, which can later progress to cardiac arrhythmias and seizures.

Fatal cases occur, but thankfully are very rare. In the vast majority of cases, dogs fully recover after a few days. Long-term consequences of chocolate poisoning are certainly possible, but their severity depends on intoxication.


Without proper treatment, this total nightmare can last four days (and nights!), so if you suspect serious chocolate poisoning, you should not dance around the dog dancing with tambourine, pretending to be a doctor, but immediately contact a proper doctor. No one knows exactly how your dog will react to chocolate alkaloids, so don’t waste time: the earlier theobromine is removed, the healthier he will be.

Even after severe chocolate poisoning, dogs usually recover within two to three days.

The first thing the clinic will do is to cleanse the dog’s intestines. To stop the absorption of methylxanthines, she will most likely be given a drug to stimulate gastric emptying. The next step is to use absorbents to bind residual hazardous compounds and restore water balance. If neurological symptoms are severe, the veterinarian may prescribe an anticonvulsant to stop seizures or increased excitability, beta-blockers for high heart rate or atropine for low heart rate.

If you know for sure that the dog has only had time to eat a little chocolate, you can try to get by with plenty of fluids and frequent walks. Theobromine, as I wrote earlier, has diuretic properties, and drinking plenty of fluids with the opportunity to urinate frequently will prevent the methylxanthines from being reabsorbed from the bladder and speed up their elimination from the body.

Watch your dog closely so that if his condition worsens, he can see a doctor. Oh, and one more thing. Dogs are incredibly curious, and like humans, love sweets. Don’t tempt them: store chocolates, especially those meant for baking (most often forgotten), in a way that eliminates the possibility of poisoning, which means high enough and in a tightly closed container.

Take care of your dogs.