The toenail is black with the following points: 1, fungal infection: general fungal infection will lead to toenail discoloration, hollow shell, it is recommended to do fungal immunofluorescence examination to confirm the diagnosis of infection, if the diagnosis is fungal infection, it is recommended that antifungal treatment can. 2, extrusion or collision: general shoe extrusion or collision will appear local toenail deformation or black color, generally this situation does not require treatment, iodine volt sterilization can be. The company’s main business is to promote the development of the company’s products and services.