A small study published in the Journal of the American Board of Family Medicine tested whether VapoRub had a positive effect on those with toenail fungus. The study, focused on 18 people who used VapoRub on their toenails for 48 weeks, concluded the ointment can help.
Dana Stern, MD, a dermatologist and nail specialist based in New York City, explained why the study (and the overall remedy) should be taken with a grain of salt. "One of the biggest issues with self-treating using home remedies is that the diagnosis is not correct," Stern explained. "Not all yellow, thick, abnormal toenails are fungal; in fact, half are not." She suggests seeing a dermatologist if your VapoRub "treatment is not working after four months for toenails and two months for fingernails."