Although the clinical features of lymphedema are often distinctive, it is essential to confirm the diagnosis with an objective test. Isotope lymphography is simple and 95% accurate for defining deficient lymph clearance. It is particularly useful for separating venous from lymphatic edema. Definition of the precise abnormality--peripheral lymphatic obliteration, proximal lymph node obstruction, or valvular incompetence--can only be made with lymphangiography. The mainstay of treatment is the reduction of edema by regular elevation and massage and external compression with elastic stockings. Pneumatic leggings are also helpful. Gross edema caused by peripheral obliteration may be reduced surgically by simple excision (Homans' operation) or complete excision and skin grafting (Charles' operation). Reflux through incompetent vessels may be prevented by vessel ligation. Obstruction by the iliac lymph nodes may be bypassed with an enteromesenteric pedicle.