Chocolate Toxicity In Animals

Chocolate can be a killer! Although chocolate is one of our favourite treats, it contains a substance that is poisonous to animals. Toxicity, or poisoning, is most common in dogs because of their habit of rapid consumption, but it may also affect cats and other pets.

What is chocolate toxicity?

Chocolate toxicity (poisoning) is caused by excessive intake of methylxanthine alkaloids which can be found in chocolate, coffee, tea and some over-the-counter stimulants. The poisoning affects many organ systems, and animals of all ages are susceptible.

Toxicity is common in dogs because of their habit of rapid consumption, and more so for puppies and young dogs as they may be more likely to ingest large amounts of unusual foods. Since chocolate is often readily available and tasty, any dog's access to chocolate goodies is a problem.

Although dogs are the most susceptible, the toxin has been known to affect or kill cats, birds, rodents and reptiles as well.

What causes chocolate toxicity?

Methylxanthine alkaloids are naturally occurring drugs (primarily theobromine and caffeine) in chocolate, coffee and tea, as well as in some over-the-counter medications. These drugs cause constricted blood vessels, a rapid and weak heartbeat and stimulation of the nervous system.

In most cases, dogs are poisoned by eating the processed chocolate used in sweets, chocolate bars and baking, since these contain high concentrations of theobromine and caffeine and dogs find them tasty. Chocolate preparations contain different concentrations of active compound. The biggest threat is from cooking chocolate, followed by semi-sweet chocolate, milk chocolate, and hot chocolate.

What are the signs of chocolate toxicity?

Vomiting and diarrhoea often occurs 2 to 4 hours after chocolate ingestion, with chocolate possibly being present in the vomit. A stimulated nervous system may present as hyperactivity, tremors or seizures and your pet's heart rate may become increasingly rapid and irregular. Your pet may also urinate more than usual due to the diuretic (water clearing) action of the chocolate.

Advanced signs of toxicity include stiffness, excitement, seizures, or extreme responses to noise, light or touch. Heart failure, weakness, coma and even death can occur 12 to 36 hours after ingestion.

How is chocolate toxicity diagnosed?

Chocolate toxicity can look similar to many poisonings or other conditions. Serious poisoning such as that caused by strychnine, amphetamines and pesticides (including some rodenticides) can cause similar symptoms.

If you suspect your dog has ingested chocolate and you are seeing any combination of vomiting, nervousness, or weakness, take them to your veterinarian or local emergency vet immediately. If possible, bring any vomit to the clinic as well, since this may aid in rapid identification of the toxic substance.

Your veterinarian will need to examine your dog's nervous system and cardiac function carefully. They may want to test the blood and urine concentration of glucose (blood sugars) and of the active ingredients in the chocolate. Since this type of toxicity progresses rapidly, signs may need to be treated symptomatically until a laboratory diagnosis is confirmed.

How is chocolate toxicity treated?

If your dog is having a seizure, do not attempt to cause vomiting; take him or her to your veterinarian without delay. If the chocolate has just been consumed, ring your vet for advice immediately.

There is no antidote for chocolate poisoning. Your veterinarian may use drugs to induce vomiting if the chocolate was consumed within the previous 2 to 4 hours, or they may use a stomach tube and fluids to clear the stomach of chocolate, followed by activated charcoal treatment to prevent any drug remaining from being absorbed.

In dogs with advanced signs, specialised medications are needed to control the seizures and to correct the dog's rapid and weak heartbeat in order to prevent heart failure.

What is the prognosis for chocolate poisoning?

The expected prognosis of chocolate toxicity is 12 to 36 hours, depending on the dosage and effectiveness of treatment. Your pet's likelihood of recovery is good if the chocolate is removed within 2 to 4 hours of ingestion. Unfortunately, a full recovery is less likely in animals with advanced signs such as seizures and serious heart dysfunction.

Given the fast progression of chocolate toxicity, it's vital to keep your chocolates, cakes and chocolate-coated goodies safely away from your pets. It's not just the chocolate that is the problem - foil and plastic wrappers can also cause intestinal obstructions. Stick to healthy treats if you want to reward your special furry or feathered friend.

Contributors: Dr Julia Adams BVSc  

By Provet Resident Vet - Last updated 1 March 2018

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