Of all the home cures for dandruff, one of the oddest ones has to be rubbing mouthwash in your hair. It may sound crazy, but it also just might just work. Listerine, or any similar mouthwash with antifungal ingredients, may be effective at killing the yeast infection which causes dandruff.
History
According to Kilmer House, a blog sponsored by Johnson & Johnson to educate the public about the company's history, Listerine did not get its start as a mouthwash. It was developed as a surgical antiseptic in 1879 and named after physician Sir Joseph Lister, who pioneered the concept of antiseptic surgery. It was advertised for its germicidal properties and used to clean wounds, soothe insect bites, and to treat fungal infections such as athlete's foot and dandruff. It wasn't until 1895 that anyone even suggested oral use, and Listerine was available only to physicians until 1914. Then in 1921, Listerine was first advertised for "halitosis", and the rest is history.
What Is Dandruff?
Dandruff is the common name for a condition called pityriasis capitis. This is a specific variety of the broader diagnosis of seborrheic dermatitis, a common but harmless scaly skin rash. Contrary to what you might think, dandruff is not caused by dry skin, but "appears to be related to the yeast" called Pityrosporum ovale, reports Dr. Ray Sahelian on his website RaySahelian.com. P. ovale is commonly found on human skin and normally does no harm, but when it grows out of control it causes seborrheic dermatitis.
Listerine's Antifungal Properties
The most effective dandruff treatments are antifungal medications, which prevent the yeast responsible from being able to grow rather than just treating the symptoms of dry, flaking skin. Listerine lists its components as eucalyptol --also known as 1.8-cineole, menthol, methyl salicylate and thymol. Two studies available at Springer Link, show that these four components all have antifungal properties.
Warning
Using Listerine for dandruff treatment has few negative side effects. The only concern would be that, since it is an antiseptic, it will burn if it comes into contact with broken skin, which dandruff sufferers may have from scratching. If your scalp burns after application, rinse the Listerine out and wait a few days for the skin to heal before trying again. Or leave it in; the burning may be irritating but will do no harm.
Does It Work?
Although there is no medical evidence that Listerine is effective at fighting seborrheic dermatitis or other fungal infections, the individual ingredients have been shown to have antifungal properties. However, it is at best a weak antifungal medication. Listerine might help for mild cases of dandruff, but moderate dandruff can generally be treated with over-the-counter shampoos.