Gray nails, also known as onychomycosis, are caused by fungal infections. The efficacy of drugs varies from person to person, and there is no so-called strongest penetrating ointment, the commonly used topical drugs are cyclopiazepoxide powder, amorphophine hydrochloride powder, etc. The most common topical drugs are cyclopiazepoxide powder and amorphophine hydrochloride powder. 1.Ciclopirox is a topical antifungal drug used for superficial skin fungal infections such as ringworm, tinea cruris, tinea cruris, tinea pedis, tinea pedis, and tinea pedis, and is also suitable for onychomycosis. Adverse reactions are local redness, itching, burning sensation, occasional contact dermatitis. Children are prohibited, and those who are allergic to the drug are prohibited from using it. 2. Amorolfine hydrochloride application: it is a topical antifungal drug for skin, used for skin fungal diseases caused by skin fungal infection, such as tinea pedis, tinea cruris, tinea cruris, tinea corporis, tinea cruris, and skin candidiasis. Very few patients will experience skin erythema, itching and rare contact dermatitis after use. Because the drug is difficult to penetrate the nail plate, it is recommended to use a knife or a nail file to remove the diseased nail as much as possible before using the drug, and then use glacial acetic acid solution, or urea ointment to seal the package to make the diseased nail soften and peel off before using the drug. Nail fungus should go to the hospital in time to check, the drug needs to be used under the guidance of a professional doctor.