Dry and frizzy hair can be dealt with by medication, dietary control, life management, etc. Different approaches can be taken according to different causes, the common causes are ringworm of the head, seborrheic dermatitis, malnutrition, and poor living habits. 1. Ringworm of the head: you need to clean up the hair, then apply antifungal ointment such as ketoconazole, clotrimazole ointment, etc., oral itraconazole, terbinafine and other antifungal drugs. 2. Seborrheic dermatitis: you can use selenium disulfide lotion to wash your hair, external calcium-modulated phosphatase inhibitors such as tacrolimus ointment and other drugs, if necessary, can be combined with oral vitamin B1, vitamin B6 and other drugs. Also pay attention to regular cleaning of the scalp. Reduce the intake of high sugar, greasy, spicy stimulating food. 3. Malnutrition: If there is a lack of nutrients needed by the hair, such as vitamins, trace elements (calcium, zinc), protein, etc., it will lead to malnutrition of the hair and dryness and roughness. 4. Bad habits: If you use poor-quality shampoo or conditioner, the harmful chemicals in it can easily damage your hair; frequent perming and coloring of hair can also damage your hair, thus causing dry and rough hair. There may be other reasons for hair dryness and roughness, it is recommended to go to the hospital in a timely manner, a clear diagnosis, symptomatic treatment, medication should be used in accordance with medical advice.