The Lanham Act was passed in 1946 pursuant to Congress’ power to regulate commerce. Section 43 of the Act prohibits false and misleading advertising, stating that “any person who uses in commerce any false or misleading description of fact, or false or misleading representation of fact, which . . . in commercial advertising or promotion, misrepresents the nature, characteristics, qualities, or geographic origin of his or her or another person’s goods, services, or commercial activities, shall be liable in a civil action by any person who believes that he or she is likely to be damaged by such an act.” This section of the Act was at the center of a recent Listerine ad campaign.

In June 2004, Pfizer, Inc. (“Pfizer”) launched a consumer advertising campaign for its mouthwash Listerine. The campaign included print ads and product tags that featured an image of a Listerine bottle balanced on a scale against a white container of dental floss. The campaign also featured a television commercial wherein the announcer stated “Listerine’s as effective as floss at fighting plaque and gingivitis. Clinical studies prove it.” Although the commercial cautioned that there is no replacement for flossing, the commercial repeated two more times the message that Listerine is as effective as flossing against plaque and gingivitis. It also showed a narrow stream of blue liquid flowing out of a Cool Mint Listerine bottle, then tracking a piece of dental floss being pulled by a white floss container and then swirling around in between teeth — bringing to mind an image of liquid floss.

McNeil-PPC, Inc., the market leader in the sale of string dental floss and other cleaning products, filed suit alleging that Pfizer had engaged in false advertising in violation of Section 43 of the Lanham Act. McNeil contended that Pfizer’s literal or explicit claim that clinical studies prove that Listerine is as effective as floss against plaque and gingivitis is false. It also alleged that Pfizer’s advertisements implicitly are claiming that Listerine is a replacement for floss and that all the benefits of flossing may be obtained by rinsing with Listerine, which is false and misleading.

The Court agreed with McNeil and on January 6, 2005 issued a preliminary injunction. The Court concluded that the two studies did not stand for the proposition that Listerine is as effective as floss against plaque and gingivitis. The studies only included individuals with mild to moderate gingivitis and excluded individuals with severe gingivitis or any degree of periodontitis. Thus, the literal claim in Pfizer’s advertisement was overly broad and consumers could have been misled by the advertisement. Second, the claim was false because the studies only prove that Listerine was effective as improperly used floss. The studies were not sufficiently reliable to permit one to conclude with reasonable certainty that Listerine was as effective as floss in fighting plaque and gingivitis.

The Court also concluded there was implied falsity that Listerine was a replacement for floss; the benefits of flossing could be obtained by rinsing with Listerine; and that those consumers who did not have the time or desire to floss could switch to Listerine instead. The implied message was confirmed by words and images, namely a stream of blue liquid tracking floss as it is removed from a floss container and then swirling between and around teeth and a bottle of Listerine balanced equally on a scale against a container of floss. Although the ads stated floss daily, the few words in the disclaimer were lost when the ads were considered as a whole. Thus, the implicit message was false, contrary to Pfizer’s argument that Listerine provided all the benefits of flossing.

The Court enjoined Pfizer from communicating these claims in its advertising materials and ordered the parties to discuss a recall of the Listerine bottles that feature the hanging tags.