Usually, gray nail refers to onychomycosis, onychomycosis patients only apply ointment not eat antifungal drugs to cure the chance is not very big. The effect of local drug treatment is limited, mainly due to the special anatomical structure characteristics of the nail plate, and the slow growth of the nail, it is difficult for the drug to penetrate into the nail plate, resulting in insufficient concentration of local drugs. Therefore, patients with onychomycosis only coated ointment not eat antifungal drugs to cure the chance is not very big. Patients with onychomycosis need local medication with antifungal drugs, such as terbinafine tablets, itraconazole capsules, etc. As treatment is more difficult, the key is to adhere to the medication. Infected nails may become a source of infection for the fungus to spread among themselves and the population. Patients should use a special foot wash basin and not mix it with others to avoid infecting others. It is recommended that patients with onychomycosis go to the hospital in time and follow the doctor’s instructions for treatment to avoid delay.