Years ago, I worked at a candy shop that specialized in chocolate. My favorite part of the job was turning ordinary food into chocolate-dipped treats. We dipped fruit, cookies, pretzels -- anything that might be improved by a coating of chocolate.

We also dipped dog biscuits, in case fond pet owners were feeling indulgent. These we dipped in white chocolate. In all likelihood, this was a sweet candy coating rather than an actual chocolate product, and probably contained no cocoa powder or cocoa butter.

That's good, because all chocolate products are toxic to dogs.

They are also unhealthy for cats and other pets, but dogs, according to several pet care and science web sites, are the most at risk.

This may be in part because of the way dogs eat. Instinctively, they gorge down all of any food available that appeals to them. Also, dogs, unlike cats, can taste and enjoy sweets.

(A cat owner I know told me, when I mentioned I was researching this article, that cats can and do fall in love with chocolate just as dogs do.)

So was I right to panic when I dropped a crumb of brownie on a friend's floor and her dog was happy to help "clean up"?

Well, it probably wasn't ideal to expose the animal to a sweet he could develop a taste for. But in terms of toxicity, such a small amount of chocolate was essentially meaningless.

For dogs and other animals, the lethal ingredient in chocolate is theobromine. Theobromine is a naturally occurring chemical whose name means "food of the gods."

Like its cousin caffeine (which chocolate also contains in significantly smaller quantities), theobromine is a stimulant that affects the nervous system. Too much of it wouldn't be good for humans, either; but the quantities that occur in chocolate are only enough to impart a mild euphoria to us.

In considering how animals will be affected by ingesting chocolate, there are two factors to keep in mind: the concentration of theobromine, and the weight of the animal.

The darker the chocolate, the higher the concentration of theobromine. Many sites that discuss chocolate and pets don't even mention white chocolate as a threat; one that did said, essentially, that a dog would have to eat many times its own weight in white chocolate in order to be at risk.

Milk chocolate is next in order of toxicity to animals, then dark, and then of course unsweetened. Chocolate cakes and other chocolate baked goods are health hazards for your pets as well.

If you have pets, it's especially important to keep baking chocolate in a place that they can't possibly reach. Depending on the size of the animal, as little as an ounce or less might be enough to threaten his life. By the time your dog notices that the flavor doesn't match the sweet promise of the scent, it could be too late.

Unsweetened cocoa powder and even sweet instant cocoa also pack quite the theobromine wallop. Milk chocolate (the most common chocolate in American households) is less of a threat, and of course candies that are only coated with chocolate have less theobromine than a chocolate bar.

But remember, you don't want your dog to develop a taste for chocolate. Best not to risk even a "safe" quantity. If chocolate is on the menu, don't share dessert, no matter how pleading your dog's expression is.

If your dog does ingest chocolate, seek medical care immediately. Keep a level head and be able to supply information regarding how much chocolate, as well as what kind, was consumed.