"You can become an All Night Lover."

"Gain up to 3 inches."

"Enjoy explosive sex tonight and every night... no matter how old you are!"

Sex sells. It sells skimpy lingerie, alluring perfumes, and steamy romance novels. But herbs and vitamins? You bet. A few examples:

• Goofy "Bob" pops up with a big grin on his face in TV commercials on CNN, ESPN, and NBC because his nether regions have been supersized by an herbal concoction called Enzyte.
• Unsolicited e-mails for "herbal Viagra" or for supplements from "Mr. Gigantic" or "Mr. Thick" flood your inbox.
• Ads with couples in erotic poses supposedly enjoying spine-tingling sex delivered by "revolutionary new all-natural" herbal formulas now appear regularly in newspapers like USA Today.

"One would have thought that most over-the-counter sex products would have disappeared with the new safe and effective drugs for male sexual dysfunction, like Viagra, Levitra, and Cialis," says urologist Irwin Goldstein of the Boston University School of Medicine. "But what has happened is the complete opposite."

Pin part of the blame on Viagra. "Viagra established that one small pill could make a big difference in sexual performance,"says Goldstein.

And if a prescription drug can do it, why can't an over-the-counter supplement? "Consumers have trouble distinguishing one slick ad from another," says Goldstein. Advertisements for the herbal supplement Enzyte were designed to look just like ads for prescription drugs, even down to using a phony Latin name, suffragium asotas (caveat emptor would have been more appropriate).