The law enforcement actions were taken last week as a result of a project started last year to identify websites making unsubstantiated cure claims, the agency said as reported by media reports Monday.
There appeared online sites that asked for a price or cheated by promising to "cure any cancer" with concoctions of herbs, systematized program of thinking good thoughts or simply mumbo jumbo.
"We found all of these claims to be nothing short of breathtaking, and not in a good way," said Lydia Parnes, director of the FTC's Bureau of Consumer Protection.
Actions against 11 companies were meted out, she announced, with six of them having already reached settlements with FTC and the remaining to be litigated.
There was no lack of Internet sites in the U.S. and outside that sell "snake oil to consumers," advertise "a treated water" or claim to "virtually eliminate the chance of getting cancer."
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One hundred and twelve sites were originally identified by the project as making non-medical cancer-cure claims, but each of them was sent warning letters that "they must have adequate substantiation for any health claims they make about their products," Parnes said.
Parnes said that the FTC was launching a website to provide educational materials about spotting and reporting bogus cancer claims.
Investigations and legal actions would continue, she said. "This is not a kind of once-in-a-blue moon effort," Parnes said. "We have been on this beat for quite a long time, and we intend to stay there."
Meanwhile, in a statement, the Federal Drug Administration said it also might take action against some sites identified in the Federal Trade Commission investigation.