- Abietic acid, a texturizer in soaps, is harmless when injected into mice but causes paralysis in frogs.
- The American Medical Association frowns on medicated makeup, because their potential to do harm often outweighs their benefit.
- Mayonnaise is as effective a dry-hair conditioner as the expensive preparations.
- Milk is a good face wash, but you'd better rinse it off well, or rancidity will give rise to bacteria that will cause pimples.
Don't skip the introduction, a provocative discussion of "cosmeceuticals," anti-aging products, what's really meant by the word "natural," "culture and cosmetics," and what to do if you have an adverse reaction. This is the fifth edition of this guide, which originally appeared in 1978. Even if you own the fourth edition, you'll want to update, because this edition includes 1,400 newly developed chemicals and hundreds of name changes. --Joan Price