Thick, yellow, hard and hollow nails are commonly associated with onychomycosis, which needs to be treated with antifungal drugs as prescribed by the doctor. Onychomycosis is a kind of nail lesion caused by dermatophytes invading the nail plate and under the nail, which can lead to the symptoms of thick, yellow, hard and hollow nails, and can be treated with topical medications such as amorphophallus application and cyclopyrrolidone application, and antifungal medications such as terbinafine and itraconazole can be taken orally. If the medication is not effective, the treatment can be combined with photodynamic therapy and nail extraction if necessary. In addition to the above diseases, other factors can also lead to the symptoms of thick, yellow, hard and hollow nails, it is recommended to consult a doctor in time to identify the cause and ask the doctor to deal with it.