Listerine promised to prevent colds — the FTC made it spend $10M saying it couldn't

For roughly fifty years, Listerine's advertising claimed the mouthwash prevented colds and sore throats or lessened their severity — winter campaigns telling readers that gargling with Listerine was insurance against the season. The FTC finally acted in 1975: after a long proceeding it found the claims false and ordered more than just stopping them. Warner-Lambert had to run corrective advertising, spending at least $10 million telling consumers: 'Contrary to prior advertising, Listerine will not help prevent colds or sore throats or lessen their severity.'

Warner-Lambert appealed, arguing corrective advertising exceeded the FTC's power and was unconstitutional compelled speech. In August 1977 the D.C. Circuit affirmed: the Commission may order corrective advertising to dissipate the effects of past deception, and the required statement was neither vague nor compelled opinion. The Supreme Court denied certiorari in 1978, letting the order stand. It was the first litigated corrective-advertising case, and the $10 million spend — roughly a year of Listerine's budget — became the measure of what a deeply believed false claim costs.

Listerine's fate defines the remedy for brand-building deception: the belief outlives the ad, and the advertiser pays to dismantle it. Every corrective-advertising order since cites this case as its foundation.