A California court has thrown out a class action suit attacking Listerines claim that its mouthwash is as effective as floss when used regularly.

The suit, originally filed in 2004, concerned Listerine commercials claiming that a quick, easy rinse with Listerine Antiseptic twice a day is actually as effective as floss. Those clinically proven claims were based on two studies conducted by the American Dental Association, which showed that twice-daily Listerine use actually reduced plaque and gingivitis more than old-fashioned flossing.

While both studies met the ADA's scientific criteria for bona fide research, they were also funded by Pfizer, which just happens to be the company that makes Listerine. And the Listerine website, which echoed the TV commercials, took pains to point out that Listerine is not a replacement for floss.

The class apparently agreed, and filed suit alleging breach of warranty, false advertising, and fraudulent business practices. The suit was brought on behalf of all persons who purchased Listerine with labels that state 'as effective as floss,' in California, from June 28, 2004 through January 27, 2005.

The Court of Appeal for California's Second Circuit, however, ruled that the class definition was overbroad, since many class members, if not most, were never exposed to the alleged misrepresentations and are not entitled to restitutionary disgorgement. The court noted that of 34 different Listerine mouthwash bottles, 19 never included any label that made any statement comparing Listerine mouthwash to floss.

Two strikes

It was actually the second time that the court decertified the class. The California Supreme Court sent back an earlier decertification order with instructions to reconsider in light of a recent landmark case, In re Tobacco II.

That case held that a class of smokers was properly certified since cigarettes were marketed as part of a massive, sustained, decades-long fraudulent advertising campaign. The Listerine court held the tobacco ruling inapplicable, since the present action only applied over a six-month period and the undisputed evidence shows many, if not most, class members were not exposed to the 'as effective as floss' campaign.

The court went on to hold that even lead plaintiff Steve Galfano was unqualified to represent the class, noting that Galfano testified that he did not make his purchase based on any of the four television commercials or other ads. And although Galfano bought Listerine due to the bottle's red label which he recalled said 'as effective as floss,' many labels also advised consumers to continue flossing, so Galfano couldn't say that his experience was representative of the class.

Even without Galfano's suit, though, the law may have had the last laugh regarding Listerine's campaign. In early 2005 -- just before Galfano filed his suit -- Judge Denny Chin of New York ordered the company to stop the ads, noting that substantial evidence suggests that no amount of mouthwash can replace daily flossing.

Dentists and hygienists have been telling their patients for decades to floss daily, Chin wrote in his order. They have been doing so for good reason. The benefits of flossing are real -- they are not a 'myth.' Pfizers implicit message that Listerine can replace floss is false and misleading.