From March 1986 to December 1987, a vaginal contraceptive, not yet commercially available in Germany, was studied in 56 women. The substance benzalconium chloride (BZC) was contained in vaginal sponges (n = 46), pessaries (n = 4) and cream (n = 6) at a dose rate of 1.18%. BZC is a surfactant of the ammonium series that ruptures the spermatozoal membrane. It is also a powerful bactericide and viricide. The advantages of the vaginal sponge (intercourse is safe immediately after insertion for the next 24 h and for multiple intercourses) made it pleasant for the women. The rate of transitory local side effects (16%) was acceptable. The vaginal contraception did not interfere with the sexual life. In 645 months of use 10 pregnancies occurred of which 9 happened with the sponge (PI 20.3). Its fixation before the cervix and the release of the spermicide is not reliable enough, so that we cannot recommend the sponge as a safe vaginal contraceptive.