Short black fine lines on the nails may be related to trauma, nail dystrophy, fungal infection, onychomatous nevus and other conditions, and should be handled through life modification, medication, surgery, etc., depending on the cause. 1. Trauma: If it is caused by trauma, usually no special treatment is needed, as time goes by, the nails will grow outward, and then the grown nails will be cut off. 2. Nail dystrophy: If there is nail dystrophy, you can usually supplement the food containing iron or hemoglobin, and also take oral multivitamins if necessary. 3. Fungal infection: If the nail is infected by fungus, it can be treated by applying drugs such as amorphophine, and in serious cases, it can be combined with oral terbinafine, itraconazole and other antifungal drugs. 4. Nail nevus: Since nail nevus has the possibility of cancer, it needs to be removed through surgery in time to prevent the lesion. It is suggested that patients should consult the doctor in time to clarify the cause of the disease and actively cooperate with the doctor for treatment, and should not use medication on their own.