Pathophysiology of lymphedema is not an enigma. It is caused by a low-output failure of the lymph vascular system in combination with an inadequate scavenging of stagnating plasma protein by macrophages. Axillary venous diseases alone never cause chronic postmastectomy edema. In the diagnosis of lymphedema, invasive methods (i.e., direct lymphography and venography) are not only unnecessary but are potentially harmful and do not give any information of therapeutic relevance. Lymphedema of the limbs without reflux of lymph or chyle is not a surgical disease. It can be treated successfully by the skillful application of specific physiotherapeutic measures free of any side effect. The results of this therapy can be maintained if the patient's compliance is good.