Gray nails, also known as nail fungus, are fungal infections of the nail plate and underlying nail tissue caused by dermatophytes, yeasts and molds. In mild nail fungus, nail coatings such as amorolfine and ciclopirox can be used alone for 3-6 months topically; in moderate nail fungus, oral antifungal drugs such as terbinafine, itraconazole, fluconazole can be considered; in severe nail fungus, oral antifungal drugs combined with topical nail coatings are considered; if the condition is very severe and the affected nail is hyperkeratotic and more than 3 mm thick, surgical nail extraction is considered, followed by short course of oral medication. For mild to moderate nail fungal disease of the foot and younger age use a short course regimen of terbinafine 250 mg/d for 4-9 weeks or itraconazole 400 mg/d for 7 days/month for a total of 2 shocks; for patients with moderate to severe foot disease, use a long course regimen of terbinafine for 9-12 weeks or itraconazole for 3-4 shocks, both of which have good after-effects and after stopping Higher concentrations of the drug remain in the nail for 3-9 months.