Gray nails are a fungal disease of the nail caused by a fungal infection and are contagious. Gray nails can be cured with treatment, but can be infected again after being exposed to the fungus causing gray nails. Therefore, gray nails cannot be called eradicated, but only cured. The main two methods of treatment for grey nails are: first, external medication, you can use topical amorolfine nail application, ciclopirox nail application, bright nail, etc.; second, internal medication, you can take oral itraconazole capsules, once 0.2 grams, twice a day, take a week stop three weeks, for a course of treatment, take three consecutive courses; you can also take oral terbinafine hydrochloride tablets, once 0.25 grams, once a day. Take it for 18-24 weeks continuously.