To review the use of sclerosing foam in the treatment of varicose veins, to describe the different techniques of foam preparation, and to report the complications of our 3-year experience with this treatment. From November 1997 to the end of October 2000, 453 patients were treated with a sclerosing foam for large, medium, and minor varicosities with sodium tetradecylsulfate (STS) or polidocanol (POL). A first group of 257 patients (90 for minor varicosities and 167 for medium to large veins) received a sclerosing foam according to the Monfreux technique. From December 1999 to October 2000, 196 patients were treated with a sclerosing foam prepared according to Tessari's method (36 for minor size veins or teleangectasias and 170 for medium-large veins). Every patient was studied with (color-flow) duplex scanning before and after the treatment and large vein injections were administered under duplex guide. The immediate success rate was 88.1% in the first group for the medium-large veins. In the same districts we registered an early success rate in 93.3% for the patients treated with the Tessari's method. The complication rate (mostly minor complications) was 8.5% in the first group and 7.1% in the second group. The use of sclerosing foam may become an established therapy in the treatment of varicose veins with a high success rate, low cost, and low major complication rate. According to our actual experience and knowledge, the safe amount of foam should not exceed the 3-ml limit, but further advancements could come from standardization of the foam preparation technique.