Purple blood on legs may be caused by capillary dilatation, thrombocytopenic purpura, and allergic purpura. It is recommended to make a clear diagnosis and can be treated by physical therapy and oral medication. 1. Capillary dilatation: purple blood on the legs may be capillary dilatation, such as long-term standing work, heavy physical labor, obesity, prone to this situation. It is recommended to pay attention to rest, do not stand for a long time, moderate exercise, is conducive to reducing weight. If you feel that it affects aesthetics, it can be treated by laser. 2. Thrombocytopenic purpura: Thrombocytopenic purpura is considered to be related to infections, diseases and immune factors. The principle of disease treatment is mainly to reduce platelet destruction and increase platelet production. Can be given under the guidance of the doctor Romistein, Terbio and other platelet-raising drugs. Dexamethasone and prednisolone can also be given to reduce platelet destruction. 3. Anaphylactic purpura: Anaphylactic purpura belongs to the vascular inflammatory reaction, which may spread to many small blood vessels all over the body, resulting in purple blood on the legs. Glucocorticoid drugs can be given, such as prednisone can inhibit the inflammatory reaction and relieve symptoms. Medications such as rutin and vitamin C may also be given. Purple blood on the legs, but also to understand whether it is related to the bones and muscles grow too fast, caused by growth lines. It is recommended to go to the hospital for a clear diagnosis and targeted treatment. Drugs need to be used in accordance with medical advice.