Nails with vertical lines are generally normal physiological phenomenon, but do not rule out gray nails, melanoma and other diseases caused. 1. Normal physiological phenomenon: with the growth of age, the function of the cells of the nail matrix in the root of the nails will be reduced, and the phenomenon of vertical lines on the nails may occur. 2. Gray nails: when the local nail tissue damage, the fungus invades the nail plate and the nail plate, causing nail color change, vertical lines, thickening, atrophy and other symptoms, which is manifested as the phenomenon of vertical lines on the nails. 3. Nail cell nevus: when there is a pigmented nevus in the cells in the root of the nail, and when there is excessive secretion of melanin in the nail cell, the symptom of vertical nail lines will appear. When the symptoms appear, it is recommended to go to the regular hospital in time for examination and confirmation, to clarify the cause of the disease, and to carry out targeted treatment under the guidance of professional physicians.