Over the last few millennia, humans have put a lot of effort into looking good. Primitive people used twigs to keep their teeth clean, the ancients used fragrant and naturally frothing plants to clean themselves, and Roman women dabbed on creams made with olive oil, rose water, and saffron to keep their skin glowing. Many of the ingredients used in modern lotions and potions are the same as our forbears used — and many more are synthetic concoctions that may actually do more harm than good.