The author evaluates the importance, technique, mechanism of action, complications and relapses of varicosities treated by sclerotherapy. With improving technique complications are diminishing. Their incidence is minimal and not higher than after surgical operations. In the investigated group of 2250 treated patients within ten years 80.7% major varicosities and 40.5% perforating veins relapsed. The incidence of relapses, in particular of perforating veins depends on the accurate diagnosis. From a group of 7500 patients who attended our out-patient department the most serious complications were two cases of embolism of the lungs and one anaphylactic shock. There was a total of 0.37% serious complications. With regard to all aspects, the author reached the conclusion that sclerotization performed lege artis can be extended in ambulatory practices. However, it is better to operate varicosities with a large lumen and sclerotize their branches. The very small varicosities are influenced by sclerotization very slowly.

Keywords: Humans; Sclerotherapy /adverse effects/; Varicose Veins /therapy/