Summary of case history,　Patient Rao, male, 73 years old, sought medical attention on April 20, 2017 due to "erythema swelling and pain in both feet for 8 years, worsening for 3 months, and necrosis and ulceration for 1 month". 8 years ago, the patient had no obvious cause of redness, burning sensation, and needle like pain in both feet. Three months ago, the above symptoms worsened in the patient, with large dark erythema appearing on the dorsum and toes of both feet, causing severe pain. The patient sought medical attention from a local hospital, but the symptoms did not improve after treatment with traditional Chinese medicine. One month ago, the patient's feet became more red and swollen, and ulcers and necrosis appeared in their toes. The treatment effect in the external hospital was not satisfactory, so I came to our hospital for treatment. symptoms and signs: The patient has edema in both feet and lower limbs, which is difficult to recover due to depressions. There are diffuse dark red and purplish red patches, and purpura like edema dark patches at the distal end of the ten toes. The pain in both feet is severe, reducing when exposed to cold and worsening when exposed to heat. I am thirsty and enjoy hot drinks, mentally tired, and have difficulty falling asleep due to nocturnal pain. I urinate three times during the night, and my stool is loose and loose. The tongue is light red, the coating is greasy and slightly yellow, and the pulse is stringy.,TCM diagnosis,　Debonding gangrene(Yang deficiency and blood stasis syndrome).,Western medicine diagnosis,　Secondary erythema acrodynia; Thromboangiitis obliterans.,Therapeutic methods,　Traditional Chinese medicine treatment adopts the method of warming latent yang deficiency, while also promoting dampness, resolving qi, promoting blood circulation and relieving pain. It is treated orally with a self-designed traditional Chinese medicine formula, while being combined with external application of a Chinese medicine solution for clearing heat and drying dampness.,Clinical outcomes,　The patient's lower limb pain and burning sensation disappear, the gangrenous toe tip automatically falls off, and the movement and function of the remaining toe return to normal, with free movement.