“Jackie,” a 4-year old Maltese mix presents to your clinic after ingesting a full milk chocolate bar about 20 minutes ago. This means he consumed about 1.55 ounces according to the package the owner brought.

How many milligrams of theobromine would this be? (Hint: Milk chocolate contains about 50 mg per ounce of theobromine, the toxin we are concerned about.) Bernie weighs 15 pounds. (Answer before scrolling down...no peeking!) Then continue reading to determine if this is toxic for this patient.

A. 93 mg

B. 74 mg

C. 900 mg

D. 240 mg

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This question is asking about how many mg he ingested, so his body weight is irrelevant for this particular problem.

He consumed 1.55 oz X 60 mg/oz (oz cancel out)= 93 mg ingested

The toxic dose of chocolate can vary per patient. At 20mg/kg may be hyperactive, agitated, and have GI symptoms. Around 50mg/kg may start to have cardiac effects such as tachycardia or arrhythmias. Doses above 60 mg/kg may start to cause neurologic symptoms such as tremoring, seizures, etc. and in severe cases death may occur.

To see what effects Bernie might have, let’s take it one step further:

He weighs 15 pounds/2.2 pounds/kg = 6.8 kg

93 mg ingested/6.8kg = 13.6 mg/kg dose ingested (this is well below the 20mg/kg that may cause hyperactivity)

So by going off of the information about side effects above, Bernie is not likely to have any severe effects other than possibly some GI upset. If he just ate the chocolate, the vet may still wish to induce vomiting, or just monitor.

Here is a handy online chocolate toxicity calculator.