We all know a storehouse of common medical treatments and preventions, tidbits of information we've grown up with and have always accepted as common knowledge. Even if we scoff publicly at "old wives' tales," many of us still hold firm to the belief that those old remedies our grandmother taught us really work.

But do they? Carol Ann Rinzler bursts some balloons and reinflates others in her Dictionary of Medical Folklore.

This slim volume isn't intended to replace professional medical advice. However, it's a handy reference for anyone curious about the validity of questionable home and herbal remedies.

Can you catch a cold by sitting in a draft or by getting your feet wet? No, not without the presence of the cold virus. What about by kissing? Yes ... but it's not likely. Smokers are more likely to catch colds than non-smokers, however. And the popular "hot rum toddy" cure is a bad idea, since the alcohol interferes with your immune syndrome and increases nasal congestion. Zinc lozenges are also a false remedy (which still manage to sell like gangbusters).

Do you "feed a cold and starve a fever," or is it the other way around? Actually, Rinzler warns, both versions are bad advice. For either ailment, it's important to digest enough calories because your body is burning them faster, and it's vital to increase your fluid intake to prevent dehydration. (Although the fluid could be chicken soup or plain water -- either is equally effective.)

The book debunks the notion that cutting down on starchy foods, like pasta and potatoes, will aid in dieting. Those high carbohydrate foods are actually useful supplements to many diets.

Married people tend to live longer than singles. Carrots really are good for your eyes. Warm milk won't help you sleep -- unless you drink it with cookies. Scratching won't spread poison ivy, but it could cause an infection, and while you can't catch poison ivy by touching a person with the rash, you can catch it by handling clothes if they brushed against the plant and haven't been washed. Cold showers do inhibit sexual desire. And Spanish Fly is no aphrodisiac -- it can be toxic.

The book also addresses various superstitions with a medical slant. For instance, there is statistical but inconclusive evidence supporting the belief that the full moon affects behavior. Masturbation won't cause hairy palms, blindness or impotence (unless you feel so guilty about the action that your own will causes the problem). Chocolate does not cause acne. Can you treat a black eye with a raw steak? Yes -- if it's cold. It's the temperature which helps prevent bruising, so an icepack will help matters much more.

I have a several volumes on home and herbal remedies in my home, so when I have a specific question, there are other books I'm more apt to consult. However, for casual browsing and interesting reading, Medical Folklore is the superior choice. It's comprehensive, fascinating and fun, and Rinzler has a conversational style of relating her information.

And what about the most pervasive and enduring of medical folklore? Does an apple a day keep the doctor away? Says Rinzler: "It couldn't hurt."