The causes of cold legs in summer may be: one is kidney yang deficiency, the second is the upper heat and lower cold evidence, and the third is caused by lower extremity blood paralysis. 1. Kidney yang deficiency: the kidney belongs to the lower focal point, kidney yang deficiency, can not warm the lower focal point, so in the summer legs will also be cold. It is often accompanied by bad cold (fear of cold), fear of cold, nocturia, soreness and weakness of waist and knees. It can be regulated with Jin Gui Ren Qi Pill. 2. Upper Heat and Lower Cold: Because of the depression and congestion in the middle jiao, the fire in the heart cannot descend to the kidney, and the water in the kidney cannot go up to the heart, so there are symptoms of upper heat and lower cold, which are commonly associated with sores on the mouth and tongue, acne, insomnia, diarrhea, and coldness of the lower limbs. It can be regulated by Half-Summer Heart Laxative Soup or Wu Mei Pills. 3. Lower extremity blood paralysis: due to lower extremity blood paralysis, varicose blood vessels, poor blood circulation, resulting in cold lower extremities, can be regulated with Angelica four reverse soup. Cold lower extremity legs, should promptly go to the hospital, diagnosed by the physician medication, early treatment, do not self-medication.