Penny ate a little bit of chocolate

Penny believes every walk is a foraging expedition. And when she finds something, she has to swallow it quickly, before her humans steal it.

We've just returned from a walk around the block, during which she nabbed some chocolate from a neighbour's driveway. I'm used to the sound of chop bones being crunched - you can usually grab them out of her mouth. I'm used to the disappointing snap and pop of cooked chicken bones going down her gullet before I can retrieve them. But who expects chocolate?

Given that we're a household of chocaholics, we've done well to make sure Penny has never scoffed any chocolate in the house. (Well, there was that huge packet of sweet biscuits that disappeared from the inaccessibly high kitchen table when Penny was a puppy...)

After we arrived home I drove back to check it was milk chocolate, and then I hurried home to look on the Net for information about the symptoms of poisoning. I''m feeling more relaxed since I read a report that says a dog her size (33pounds/ 15 Kilos) would have to eat 33 ounces of milk chocolate to be in danger.

At Net.Pet Magazine I got more details. The half-life of the dangerous ingredient - theobromine - is 17.5 hours. (I like that, because it sets a time limit on my worrying.) Milk chocolate has 44 mg of theobromine per ounce of chocolate. Therefore the toxic dose for a 50 lb dog would be 50 oz of milk chocolate. I don't quite understand the maths of that, but it comes out to the same amount as the other site.

On the other hand, following a link from Dolittler, my favorite veterinary blogger, I arrived at the ASPCA and read:

Chocolate contains large amounts of methylxanthines, which, if ingested in significant amounts, can cause vomiting, diarrhea, panting, excessive thirst, urination, hyperactivity, and in severe cases, abnormal heart rhythm, tremors and seizures.

Wait a minute! I've just got my head around one big word. What is this 'methylxanthine'?

And then, on a medication guide for humans, I discovered that theobromine is a type of methylxanthine, which solved that little mystery!

At a site for vets to share information I was interested to note that dogs may, however, show symptoms at a much lower dose, as low as ten percent of the fatal dose. However, the vet says the danger from milk chocolate is very low.

But, by my calculation, that's only 3.3 ounces. So I'll be keeping an eye on her. She's barking up a storm at the front door at the moment, but I think that's just her usual reaction to next door's cat being in our front yard.