Up to 10 percent of people across all ages and as many as 50 percent of people 70 or older have this toenail fungus, according to an article published in the December 2013 "American Family Physician." Also called onychomycosis, fungus infects the nail bed and causes the nail to thicken and discolor 1. The thickening may push the nail away from the toe, sometimes causing loss of the nail. Since onychomycosis is difficult to cure and recurrence is common, treatment alternatives including Vicks VapoRub have become popular.

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If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Vicks VapoRub Ingredients

Vicks VapoRub has three main active ingredients. Camphor is a known topical anesthetic. Vicks VapoRub uses a camphor concentration of 4.8 percent in its product. Similar to camphor, menthol has anesthetic properties when applied to the skin. Eucalyptus oil is the third active ingredient. The doses of menthol and eucalyptus oil in VapoRub are 2.6 percent and 1.2 percent, respectively. Inactive ingredients include thymol, cedarleaf oil, nutmeg oil, special petrolatum and turpentine oil.

Laboratory Study With Active Ingredients

Ingredients in VapoRub have been shown to prevent growth of certain types of fungus in the laboratory setting, according to the authors of an April 2003 article published in "Phytotherapy Research." Camphor, menthol, eucalpytus oil and thymol were tested against multiple species of fungus that may cause toenail infections. Each of these ingredients was found to inhibit the growth of fungus on a laboratory culture medium at concentrations as low as 5 mg/mL, or 0.5 percent. The concentration of thymol is not documented on the VapoRub product label, but all the other product ingredients are at concentrations above those tested in this experiment. Since not all laboratory studies translate into real life situations, a research study involving a sizable number of people would be needed to see if these ingredients are truly effective for treating fungal infections in humans.

Clinical Trial With Vicks VapoRub

A clinical trial published in the February 2011 "The Journal of the American Board of Family Medicine" suggests that VapoRub may be effective in treating some cases of toenail fungus 4. In this study, 18 participants were treated with Vicks VapoRub and followed over 48 weeks. Five of study participants experienced a cure and 10 had improvement of their symptoms. Cultures of the toenails before and after treatment verified that the fungus had been eradicated in those who were cured. Of the 5 people with a cure, only 2 species of fungus were identified -- Trichophyton mentagrophytes and Candida parapsilosis. This suggests that treatment effectiveness may depend on the specific type of fungus present. As of the time of publication, there have been no other published clinical studies to support or refute these data.

Considerations for Treatment

Limited information is available regarding whether VapoRub is an effective treatment for toenail fungus. Studies are small and have not been repeated to confirm effectiveness. Still, the existing data are supportive. VapoRub may be more effective against certain types of fungus, such as Trichophyton mentagrophytes, though more studies are needed to establish this preliminary finding. Other treatments for onychomycosis, specifically prescription medications, may be expensive and possibly cause side effects. Over-the-counter treatments for toenail fungus may or may not be effective. Talk with your doctor about treatment options if you suspect you have a toenail fungus infection.