Federal regulators will announce guidelines today for advertising vitamins, herbal products and dietary supplements. The Federal Trade Commission will require proof that products do what is claimed in advertising. Since a 1994 law removed some Food and Drug Administration control over vitamins and supplements, the FTC has moved to take over regulatory oversight of the industry.

• About 100 million consumers use such supplements as St. John's Wort and Gingko Biloba.

• Advertising for the products is up more than 30 percent from 1997.

• Since 1994 the FTC has gone after supplement makers 34 times for misleading ads -- up from just 26 cases in the previous 12 years.

Supplement companies say the guidelines still give the FTC a lot of discretion, but that it has never been clear how much substantiation is needed.

Source: Jayne O'Donnell, "Government to Set Guidelines for Dietary Supplement Ads," USA Today, November 18, 1998.