Lymphedema is the most notable complication after axillary lymph node dissection. In view of the recent large number of patients suffering from untimely treatment, I would like to write a brief article to alert all sisters! There are no exact data on the incidence of lymphedema because of the different measurement methods. The most recent data comes from a randomized controlled study of axillary lymph node dissection versus sentinel lymph node biopsy, in which the incidence of moderate to severe lymphedema at 12 months postoperatively was 13% in the axillary lymph node dissection group and 5% in the sentinel lymph node biopsy group. There is no reliable clinical method to follow on how to prevent lymphedema, and some of the traditional prevention advice that is still used includes: avoiding trauma and infection; avoiding blood pressure measurement in the affected limb; and avoiding heavy weight holding or repeated strenuous exercise. Although breast surgeons generally believe that postoperative lymphedema is incurable, the author’s treatment experience shows that the milder the degree of lymphedema, the better the treatment outcome and the shorter the treatment period, thus emphasizing early treatment of lymphedema (from the time the patient first starts to experience postoperative swelling and discomfort rather than edema visible to the naked eye). Currently, the main treatment methods include medication (horse chestnut seed extract, herbal medicine, etc.), physical therapy (gradient pressure therapy, elastic bandages, functional exercises, etc.) and lymphovascular anastomosis.