Sclerotherapy in the treatment of varicose veins S2k guideline of the Deutsche Gesellschaft für Phlebologie (DGP) in cooperation with the following societies: DDG, DGA, DGG, BVP These guidelines are also consistent with the results of the first European guidelines for sclerotherapy dating from 2012 [1]. These guidelines consider the current state of the literature, but not in every case the different conditions of approval of the various drugs.