The Federal Trade Commission charged five companies with making false and misleading claims for cancer cures and said Thursday that it has reached settlements with six others.

"As long as products have been sold there has been somebody out there selling snake oil to consumers," said Lydia Parnes, director of the FTC's bureau of consumer protection.

She said the agency, along with the Food and Drug Administration and Canadian authorities, is launching a consumer education campaign warning about bogus claims for cures.

"There is no credible scientific evidence that any of the products marketed by these companies can prevent, cure, or treat cancer of any kind," said Parnes.

The products the companies marketed include essiac teas and other herbal mixtures, laetrile, black salve — a corrosive ointment — and mushroom extracts.

Douglas Stearn of the FDA said his agency is concerned that people may forego effective cancer treatments when choosing these products. In addition, he said, some of these unproven products may have dangerous interactions with other drugs.

"We would urge folks to talk to their doctors," said Stern.

Parnes said more than 100 warning letters were sent out and many advertisers dropped or changed their claims.

Of the complaints resolved by settlements, she said companies paid restitution ranging from $9,000 to $250,000.

The remaining five complaints of false and deceptive advertising will go before administrative law judges, she said.

Those cases are Omega Supply, San Diego, Calif.; Native Essence Herb Company, El Prado, N.M.; Daniel Chapter One, Portsmouth, R.I.; Gemtronics, Inc., Franklin, N.C., and Herbs for Cancer, Surprise, Ariz.