Chocolate Toxicity in Dogs

Today being Halloween, it is appropriate to promote awareness of chocolate toxicity in dogs.  Children and even many grown-ups accidentally leave chocolate and other candy lying around and accessible to dogs…who rarely can resist the opportunity to gorge on it.  While in people overindulgence of chocolate may lead to a tummy ache, even relatively small quantities of chocolate consumed by dogs could lead to severe illness and death.

Chocolate contains a compound that comes from the cocoa plant that it is derived from called theobromine.  While this compound is by in large promptly metabolized in people and therefore poses little potential harm, canines metabolize theobromine much more slowly, causing it to accumulate in the system as it is ingested.  Once it reaches a certain level in the bloodstream, a number of adverse effects may begin to occur as it has the potential to affect multiple vital organ systems.

Theobromine causes a precipitous drop in blood pressure that can lead to heart arrhythmias (abnormal heart beats) and poor blood perfusion to vital organs, such as the kidneys and liver.  Arrhythmias can lead to cardiac arrest and organ failure secondary to compromised blood perfusion are common complications and causes of fatality from theobromine consumption.

Theobromine has an excitatory effect on the central nervous system, which can lead to dangerously high fever and seizures.  Lastly, theobromine has a toxic effective on the gastrointestinal system leading to vomiting and diarrhea, often severe in nature.

All chocolate has some levels of theobromine, but some types of chocolate have more than others.  While you should always seek veterinary attention immediately for ingestion of any amount of chocolate by your canine, owners should be aware of the relative danger the different type of chocolate leads to based on their respective theobromine content.

1. Milk Chocolate – Mild signs of toxicity can occur when 0.7 ounces per pound of body weight is ingested; severe toxicity occurs when two ounces per pound of body weight is ingested (or as little as one pound of milk chocolate for a 20-pound dog).
2. Semi-Sweet Chocolate – Mild signs of toxicity can occur when 0.3 ounce per pound of body weight is ingested; severe toxicity occurs when one ounce per pound of body weight is ingested (or as little as six ounces of semi-sweet chocolate for a 20-pound dog).
3. Baking Chocolate – This type of chocolate has the highest concentration of caffeine and theobromine. Therefore, as little as two small one-ounce squares of baking chocolate can be toxic to a 20-pound dog (or 0.1 ounce per pound of body weight).

Be careful of accidental chocolate ingestion in your dogs this Halloween and holiday season when there tends to be especially high amounts of it around the home.  Keep it secured and out of reach of your dogs, as their life may literally depend on it.

Dr. Roger Welton is the President of Maybeck Animal Hospital and CEO/Chief Editor of the veterinary information and blog online community, Web-DVM.