The induction of hyperkeratotic white lesions in hamster cheek pouches with mouthwash.

Listerine mouthwash applied to the left cheek pouch mucosa of thirty-seven hamsters 45 minutes daily for 41 days caused diffuse, corrugated white lesions showing hyperkeratosis in 100 percent of the animals. The right (control) side showed essentially no changes in response to saline solution applied similarly. The significance of these findings is discussed.