A randomised, double-blind, cross-over trial was performed on 26 patients with postmastectomy lymphoedema of the arm, and 14 with lymphoedema of the leg. For 6 months, patients took 0-(beta-hydroxyethyl)-rutosides (oxerutin; "Paroven", "Venoruton", Zyma) in doses of 3 g/day, or the placebos; then they took the reverse. Measurements (volume, circumferences, tonometry and skin temperature) were made monthly. The active drug reduced the volumes of the limbs (p less than 0.05 to 0.01) and their circumferences (p less than 0.05 to 0.001). It increased the softness of the limbs, as shown by the increases in the tonometry values (p less than 0.01 to 0.001). There was a lowering of the elevated skin temperatures (p less than 0.05 to 0.001). Patients reported increased comfort and freedom of movement, a lessening of their bursting pains, heaviness and tension (p less than 0.05 to 0.01), and an increased mobility of their limbs (p less than 0.0001). Most patients (70%) preferred the active drug (p less than 0.0001). An increase in general well-being was reported by 97% of patients when taking the active drug compared with 4% for placebo (p less than 0.0001).