The spermicidal activity of oleanolic acid 3-β-d-glucuronide (OAG), an active principle isolated from root extracts of Sesbania sesban, was evaluated.Under the Sander–Cramer test criteria, the sperm-immobilizing activity of OAG was studied using highly motile rat sperm. Sperm mortality and membrane integrity were assessed by supravital staining, hypo-osmotic swelling (HOS), transmission electron microscopy (TEM) and sperm membrane lipid peroxidation (LPO). In vitro microbicidal potential and hemolytic index of OAG were examined in Lactobacillus culture and rat red blood corpuscles (RBCs), respectively. Post-intravaginal OAG application, the in vivo contraceptive efficacy was evaluated in rats. Ames test determined the carcinogenic potential of OAG.The minimum effective concentration (MEC) of OAG was 50 mcg/mL. More than 97% of the OAG-treated sperm lost their HOS responsiveness in a dose-dependent manner. TEM and LPO revealed that OAG affected the sperm membrane integrity. OAG declined fertility to zero, was nonmutagenic and was not harmful to lactobacillus.OAG has significant spermicidal activity that may be explored further.