The medical term for gray nails is onychomycosis, an infection of the nail plate and/or subnail tissue caused by various fungi. After taking oral medication as prescribed by the doctor, it takes about 6 to 9 months for a new nail to grow. The exact time it takes for the new nail to grow is related to the severity of the condition, the rate of nail growth, and the efficacy of the medication. Usually, oral medications for nail fungus include itraconazole and terbinafine. A 2- to 3-month course of treatment is required for finger nail fungus and a 3- to 4-month course of treatment is required for toe nail fungus. During treatment, a fungal test may be done to see if the fungus has been killed. If the fungus is killed, the new nail will grow slowly. If the fungus is not killed, you can continue to consolidate the treatment for 1 to 2 sessions to see if the fungus is killed. At the end of the course of treatment, it is sometimes possible to see more normal nail growth at the root of the nail. It usually takes 6 to 9 months for the nail to grow from the root to the free edge of the nail, and it can take up to 9 months for toenails, especially the thumbnails of the feet. In addition, nail growth is affected by nail nutrition, normal skin on the hand, whether the nail bed is normal, and age. Older growth will be slower and it usually takes more than 6 to 9 months to grow a completely new nail. It is recommended that patients go to a regular hospital for fungal and other tests, under the guidance of the doctor, combined with their own conditions, choose the appropriate treatment program, the use of drugs need to follow the doctor’s instructions.