Gray nails, also known as “onychomycosis”, are caused by fungal infections. There is no specific treatment for onychomycosis due to the difference in individual’s constitution and condition. Currently, medications commonly used for onychomycosis include topical and oral treatments. If the patient has a large area of onychomycosis, with much nail destruction and multiple involvement, oral medications such as itraconazole and terbinafine are usually considered. If the nail fungus is more mild and very marginal, patients can consider topical drug treatment, common ones are amorolfine application, cyclopiazide application, etc. They have good penetration and can kill the fungus deep in the nail plate, so they have good effect on nail fungus. If you have onychomycosis, it is recommended that you go to the hospital in time for treatment, and the above medications should be used according to the doctor’s instructions.