Gray nails are known as onychomycosis. Onychomycosis of the feet has been more than 40 years can be cured, but due to individual differences and different diseases, can not determine the specific time needed to cure. “Gray nails” is the common name for onychomycosis, a disease caused by fungi such as dermatophytes that invade the nail plate and subnail tissues, requiring a long course of treatment. Diseased nails often appear cloudy, thickened, peeling, uneven, and so on. Depending on the number of diseased nails, the degree of nail destruction, the type of pathogenic bacteria and the patient’s health condition, different treatment methods can be chosen. Nail fungus medication is divided into topical and systemic treatments. Topical treatment includes applying 5% amorolfine application for 48 weeks or 8% cyclopiazonic acid nail coating for more than 6 months. Systemic treatment includes oral terbinafine, itraconazole or fluconazole, and the course of treatment is usually more than 6 weeks. Combination therapy may improve the cure rate. Non-pharmacologic treatment includes nail extraction and removal of diseased nails. The special anatomical structure of the nail plate makes it difficult for drugs to penetrate, so the course of treatment is long and the recurrence rate is high. Patients should consult the doctor in the hospital and choose the appropriate treatment plan according to the specific typology of onychomycosis, so as to reduce the failure rate and recurrence rate. The above drugs should be used according to the doctor’s prescription.