“My dog ate chocolate! Is she going to be OK?”
The young woman held a fluffy brown and white Shih Tzu named Bella. As I examined Bella, I noticed she seemed anxious and was panting a lot.
Anxiety is expected when pets come to the vet clinic, but I also noticed that Bella’s heart rate was a lot faster than normal at 250 beats per minute.
Bella was showing classic symptoms of chocolate poisoning in dogs.
Dogs and humans have been cohabiting for thousands of years. We share our homes, our beds, and our food.
Bella had found the gift of dark chocolate bonbons her owner had received for her birthday and chowed down on most of them.
Everyone love chocolate, but…
The average American human happily consumes about 11 pounds of chocolate each year.
But for dogs, even a few ounces of chocolate can be enough to cause major illness.
Our dogs love eating chocolate almost as much as we do. They’ll dig it out of trash containers, pillage purses, and raid the pantry for a chance to taste the sweetness.
The ASPCA Animal Poison Control Center reported that chocolate was number five on their list of the top ten pet toxins of 2017.
So, why can’t dogs eat chocolate? The answer lies in a couple of the chemical compounds found in chocolate.
Why Is Chocolate Bad for Dogs?
Methylxanthines are organic compounds found naturally in cocoa beans.
These compounds have a stimulant effect on the central nervous system, cardiac and smooth muscle tissue.
That can be helpful when they’re used in drugs like the bronchodilator theophylline.
But too much methylxanthine can cause big problems for dogs. What happens if a dog eats chocolate?
The two methylxanthines thought to cause most of chocolate’s adverse effects in dogs are theobromine and caffeine (Gwaltney-Brant 2001).
Dogs are much more sensitive to methylxanthines than humans. Plus, when dogs eat chocolate, they often eat large quantities.
Theobromine has a 17.5-hour half-life in dogs compared to the 7-hour half-life people (Beasley 1999).
Since dogs don’t metabolize theobromine as rapidly as humans, it can build up to toxic levels very quickly.
Studies have shown that some dogs can metabolize methylxanthines more quickly, accounting for the variable effects of chocolate consumption on individual dogs (Collica 2012).
My Dog Ate Chocolate–How Long Until Symptoms Appear?
The symptoms of chocolate poisoning in dogs are usually seen within the first three to twelve hours after consumption (Beasley 1999).
Most dogs vomit soon after eating chocolate, which is actually a good thing as it removes some of the undigested chocolate from the system.
Symptoms of Chocolate Poisoning in Dogs
In addition to vomiting, you may notice your dog seems restless, anxious, or hyperactive. Picture yourself after one too many double espressos.
Owners reporting, “My dog ate chocolate!” often notice mild to severe diarrhea and decreased appetite.
More severe symptoms of chocolate poisoning in dogs include changes in heart rate and the force of each heartbeat.
In the most extreme cases, a dog’s tongue can look bluish due to poor oxygenation of the blood.
Dogs may be wobbly on their feet after eating a toxic dose of chocolate.
Increased urination can also be a sign that a dog ate chocolate. Pancreatitis can occur in the days after a dog eats chocolate.
Can Dogs Die from Eating Chocolate?
Dogs can die from eating large amounts of chocolate. The LD50 of theobromine and caffeine (the dose at which half of the dogs died) is 100-200 mg/kg.
Dogs at increased risk of death include those with pre-existing heart disease or a propensity toward pancreatitis.
Dogs can die soon after eating chocolate from the primary effects or many days later if they develop a secondary disease like pancreatitis.
Small dogs are at greater risk since the toxic effects of chocolate are dose-dependent. Bella the Shih Tzu weighed only ten pounds (4.5 kg).
Her owner figured that she had eaten about six ounces of dark chocolate.
Six ounces times 130 mg of theobromine per ounce of dark chocolate is a total of 780 mg of theobromine.
That comes out to a dose of about 173 mg/kg – definitely a toxic dose. No wonder she was showing symptoms of chocolate toxicity!
A large dog who eats a one-ounce milk chocolate bar may have mild to moderate symptoms but is unlikely to be severely affected or die from that dose.
Big dogs can handle more chocolate than little dogs, but it’s not a great idea for any size dog to eat any kind of chocolate.
Can Dogs Eat White Chocolate?
It’s not the best idea for dogs to eat white chocolate because it’s high fat and sugar content may cause digestive upset.
However, as shown in the table below, white chocolate has the lowest levels of methylxanthines and is not expected to cause as severe symptoms as dark chocolate.
(Table adapted from Gwaltney-Brant, 2001.)
A good rule of thumb is that it takes about 0.5 ounces of milk chocolate per pound of body weight to cause moderate symptoms.
It only takes about 0.2 ounces per pound of dark chocolate to cause moderate symptoms.
At lower doses, you might see milder symptoms including restlessness, vomiting, and diarrhea.
What To Do If Your Dog Eats Chocolate
- Observe your dog for unusual symptoms including vomiting, anxiousness, panting, bluish tongue, and wobbliness when walking.
- Find the packaging from the chocolate. Try to determine if your dog ate dark or milk chocolate. The label will sometimes say something like 70% cacao, milk chocolate, semi-sweet chocolate, etc. Also, determine how much your dog ate.
- Use this simple chocolate calculator to help determine the potential toxicity of the chocolate your dog ate. Another option we give people calling into my vet clinic saying, “My dog ate chocolate!” is to call the ASPCA Animal Poison Control Center at (888) 426-4435. For a small fee, they will tell you if your dog is in trouble and walk you through what to do next.
- If your dog is showing severe symptoms, take him to your veterinarian or an emergency veterinary clinic right away. The sooner he gets treatment, the better his chances of recovery.
If you find yourself exclaiming, “Oh no! My dog ate chocolate!” don’t panic. Gather your information and make some calls.
Most dogs come through the experience just fine if they receive proper treatment soon after eating chocolate.
In the future, make sure you keep anything containing chocolate safely out of reach of your dog. They love chocolate as much as you do and don’t understand that eating too much can make them very sick!
Beasley V.R., et al: A Systems Affected Approach To Veterinary Toxicology. University of Illinois College of Veterinary Medicine, Urbana, IL, pp. 116-120, 1999.
Collica S: The polymorphism 117C>^ in the cytochrome P450 CYP1A2 interferes with the metabolism of theobromine in the beagle dog. Veterinary Medicine Justus Liebig University, Giessen, Germany 2012.
Gwaltney-Brant, S. (2001). Chocolate intoxication. Vet Med, 96(2), 108-111.