Within the last couple of years, a rash of e-mails warned women that tampon manufacturers put asbestos in their tampons to make women bleed more in hopes of selling more product. Tierno says the rumor was false. "I have been privy to every manufacturer's records over the last 21 years, and I have never seen anything related to asbestos in tampons," he says.

Though the asbestos scare amounted to nothing but an urban myth, true additives to be concerned about are fragrances and deodorants. Perfumes may mask odors, but some women suffer allergic reactions to them. "Without question, a deodorized tampon is dangerous," asserts Tierno, adding that deodorants encourage overgrowth of certain bacteria, upset the vagina's normal flora and irritate the mucous membrane.

The main point, when it comes to tampon use, is to stay informed and weigh the options. "Over the years, tampons have allowed women to be more active and fuss less during their periods," says Chandler, who points out that while this is liberating, it also makes it easy to take their use for granted.

Laurel Kallenbach writes about natural health, travel and the arts.