Pfizer said that its market-leading product came under unfair attack when Proctor & Gamble claimed in a television advertisement that four out of five dentists would recommend the rival brand Crest Pro-Health mouthwash.
"P&G's false and misleading claims concerning Crest Pro-Health cause a substantial number of consumers to believe that this product is recommended by the vast majority of dentists - which is false - and that these dentists are recommending it for specific product-related reasons - which also is false," the lawsuit says.
Pfizer claims that the advertisement makes a direct comparison to the Listerine brand, painting Crest Pro-Health in a more favorable light in ads that have been aired on US television since December 2005.
Pfizer says that ultimately it intends to win back any profits that Proctor and Gamble might gain from increased sales attributed to the advertising campaign.
The lawsuit also states that some 269 dentists were asked to take place in the Procter & Gamble survey to give their opinion on the Crest Pro-Health having been paid $75 to participate.
Various press reports stated that Procter & Gamble had refused to make any comment on the proceedings.
Filed in the US District Court in Manhattan, lawsuits of this type play an important and regular part of brand protection in the closely guarded and highly competitive personal care sector. Brand owners fight hard to protect their brand's identity and regular court battle have become a part of this process.
Procter & Gamble is particularly litigious, filing any number of lawsuits every year against companies making advertising claims that threaten their brand names or else try to copy a brand's image.
Last month Procter & Gamble filed a US lawsuit against a private label manufacturer of health and beauty products, Vi-Jon Industries, alleging that the company copied its branding and packaging to market a similar product designed to compete against it.
The lawsuit alleges that Vi-Jon 'infringed and diluted the unique trade dress of P&G's Crest Pro-Health' as well as using false advertising claims against its product.
That lawsuit came just a day after Procter & Gamble reached a settlement with McLane regarding a suit it filed last December that again addressed copied packaging.
In this case it alleged that McLane sold products with packaging that copies some of its well-known toilet paper and medicine brands such as Charmin and NyQuil.