Chocolate Poisoning in Dogs

Chocolate is derived from the roasted, ground seeds of the cacao tree and contains the methylxanthine theobromine – a chemical similar to caffeine. Theobromine acts as a diuretic, heart stimulant, blood vessel dilator and smooth muscle relaxant in animals and humans. Dogs metabolize theobromine very slowly, thereby enhancing the effects and toxicity to these pets. Chocolate ingestion is a common causes of canine poisoning and can lead to illness and death. Contact a veterinarian immediately if you suspect your pet has eaten chocolate. Chocolate is toxic as it contains the methylxanthine theobromine. Theobromine is similar to caffeine and is used medicinally as a diuretic, heart stimulant, blood vessel dilator, and a smooth muscle relaxant. Theobromine can be poisonous and result in severe clinical signs, especially if untreated.

Symptoms may not appear until 6-12 hours after chocolate ingestion. Symptoms that your pet may have chocolate toxicity include:

• Vomiting
• Drooling
• Diarrhea
• Extreme thirst
• Increased urination
• Hyperactivity
• Pacing
• Panting
• Muscle tremors
• Seizures

The type and amount of chocolate ingested by your pet will determine the level of severity. The more concentrated the level of theobromine in the chocolate, the more toxic the dose.

0.2 ounces of baker’s chocolate is sufficient to cause symptoms of toxicity in a 10-pound dog. 1.6 ounces of milk chocolate is sufficient to cause symptoms of toxicity in a 10-pound dog.

Concentrations of theobromine in various forms of chocolate (generalizations):

• White chocolate – 1mg/ounce
• Milk chocolate – 60mg/ounce
• Semi-sweet chocolate – 260mg/ounce
• Dark chocolate – 300mg/ounce
• Baking chocolate – 450mg/ounce
• Cocoa shell yard mulch – 300-1200mg/ounce

Though white chocolate and milk chocolate have lower levels of theobromine, the sugar and fat content can cause potentially life-threatening pancreatitis.

Theobromine levels and effect on the body:

• 20mg theobromine per kg body weight - mild gastrointestinal symptoms
• Greater than 40mg/kg - heart arrhythmias
• Greater than 60mg/kg – muscle tremors, seizures

If you suspect your pet has eaten chocolate, treatment is initiated immediately without waiting for official diagnosis. Try to calculate how much the pet has eaten (how many candy bars, brownies, cake) and note the type and brand of chocolate (have the packaging available if possible). Be sure when scheduling a veterinarian appointment to tell her how much your pet weighs, describe when you think your pet ate the chocolate, how much, and of what type.

If the pet has not eaten a toxic amount of chocolate, a veterinarian may ask you to induce vomiting at home and/or carefully monitor your pet for symptoms over the next 4-6 hours.

If the pet has eaten a potentially toxic amount of chocolate in the last 1-2 hours, your vet will ask you to induce vomiting at home or bring the pet to the clinic to induce vomiting. The goal is to induce vomiting as quickly as possible. After 2 hours, the toxin has already entered the bloodstream and it may be too late for vomiting to aid in treating toxicity.

Your veterinarian will take a thorough history to determine whether your pet has gotten into trash, cocoa shell yard mulch, or other toxic substances or whether another underlying cause of symptoms is present. A complete physical exam will help in diagnosis.

Blood analysis (complete blood cell count and chemistry) and urinalysis will aid in detection of disease or organ failure. Electrocardiography (EKG) can detect heart arrhythmias and abnormalities. Radiographs may aid in ruling out other causes for symptoms.

By the time symptoms of chocolate poisoning appear, supportive therapy is the only treatment. There is no antidote for chocolate toxicity.

Inducing vomiting

Induction of vomiting must be done within 2 hours of chocolate ingestion to be effective. If you are too far from the veterinary clinic, your vet may ask that you induce vomiting at home. Follow the instructions given by your veterinarian carefully. 

If you decide to take your pet to the clinic to induce vomiting, the veterinarian will use a drug to induce vomiting right away.

Activated charcoal absorption

In cases of chocolate ingestion, the veterinarian will often give a solution of activated charcoal orally to absorb any remaining theobromine from the gastrointestinal tract.

After vomiting induction and/or charcoal treatment, your pet will need to be monitored for symptoms for 4-6 hours. If symptoms occur, supportive therapy will be required to keep your pet safe and stable until toxicity wears off. This can take up to 72 hours.

Supportive therapy

Intravenous fluid administration can help to dilute theobromine levels in the bloodstream and promote excretion. Benzodiazepines (valium) may be administered to control seizures and muscle tremors. Anti-arrhythmic medications can aid in controlling heart arrhythmias.

A pet that has been treated for symptoms of chocolate poisoning will need to be monitored until symptoms reside. Recovery from chocolate toxicity depends on the severity and how soon treatment was administered. Recovery can be complete and prognosis good if caught and treated early (within 2 hours of ingestion).

Chocolate poisoning can be lethal at high doses. Always keep chocolate out of reach of your pet. Hiding chocolate is not sufficient since chocolate has a strong smell and a pet can find it. Keep chocolate where a pet cannot get to it (high up and in a sealed container).

Chocolate poisoning can be expensive to treat. To avoid high vet care expenses, secure pet health insurance today. The sooner you insure your pet, the more protection you’ll have from unexpected vet costs.