Proctor & Gamble has left a bad taste in the mouth of rival Pfizer.

The consumer goods titan is being pursued through the US courts over claims that it falsely advertised its Crest Pro Health mouthwash brand.

New York-headquartered Pfizer contends the ads gained unfair advantage over its product, Listerine. It is also seeking damages at least equal to P&G's profit, gains and advantages.

Pfizer claims commercials on major broadcast and cable networks intended to compare Crest Pro Health with Listerine, causing "irreparable harm and damage to Pfizer, as well as to consumers".

It adds that Cincinnati-headquartered P&G falsely claimed four out of five dentists recommend Crest Pro Health for reasons related to the product's efficacy, superiority or other characteristics. Pfizer says its rival has "has no substantiation for either claim and neither statement is true".

P&G has so far remained zip-lipped about the lawsuit.

Data sourced from Wall Street Journal Online; additional content by WARC staff