The causes of blackening of blood vessels in the calves include varicose veins of the lower limbs and superficial phlebitis, etc. The treatment needs to be chosen according to the cause of the disease, and you can choose medication, surgical treatment, or change of lifestyle habits. 1. Varicose veins of the lower limbs: patients with varicose veins of the lower limbs can choose to change their living habits in order to slow down the progress of varicose veins of the lower limbs, or take oral medication or surgical treatment. (1) Changing life habits: patients with varicose veins of the lower limbs should avoid standing for a long time, reduce the time of heavy work, and wear elastic stockings to improve varicose veins of the lower limbs in both work and life. (2) Medication: Commonly used medicines include Mazolin tablets, Diosmin tablets, etc., which can be synchronized with the improvement of life habits. (3) Surgery: If the varicose veins of the lower limbs are more serious and the symptoms cannot be relieved by medication, it is recommended to go to the hospital as soon as possible for varicose vein stripping or other surgical treatments. 2. Superficial phlebitis: The treatment of superficial phlebitis is mainly based on medication, commonly used drugs include amoxicillin capsule, compound danshen tablets, etc. If the patient’s heat and pain symptoms are aggravated and cannot tolerate them, it is necessary to add ibuprofen tablets, celecoxib capsule and other medicines to relieve the heat and analgesic treatment.