Gray nails can be manifested as brittle, yellowish nails, loss of luster, uneven surface, horizontal lines as well as thickening of nails and atrophy of nail plate. It is medically known as onychomycosis. Onychomycosis is caused by a fungal infection of the nail or nail bed. It is usually treated with antifungal medications such as terbinafine hydrochloride and fluconazole. And it can be supplemented with topical antiseptic treatments such as ketoconazole ointment and terbinafine ointment to coat the nails. When the nails become yellow, brittle, or the surface of the nails is uneven, there are white spots or lines, we should be alert to the occurrence of gray nails, through early treatment can have better results, so you need to consult a doctor in time. The use of drugs should be under the guidance of a doctor, because antifungal drugs have an adverse effect on liver function, so they need to be used under the condition of regular review of liver function.