10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 2 2013 (April - June) Oral administration of crude aqueous extract of lessThan i greaterThan Jussiaea repens L lessThan /i greaterThan (family - Onagraceae) to adult male albino rats of Wistar strain at the doses of 100 mg ( low dose ,Group-II), 200 mg ( moderate dose, Group - III), and 400 mg (high dose, Group -IV) / kg body weight /day for 28 days, caused no significant change in body weight and organ weights like liver, kidney, spleen and heart but the weights of testis and cauda epididymis were significantly reduced in Group - III, where the weight of adrenal gland showed significant rise in Group - IV. Epididymal sperm concentration, motility and viability were significantly reduced but Sperm abnormality was markedly increased in Group - III and IV. SGOT,SGPT,ALP,ACP, Total protein, Urea and Creatinine level in serum were remained unchanged in treated groups. The fructose content of seminal vesicle and ventral prostate was reduced significantly in Group – III. All comparisons were made against the vehicle (water) treated control. So, the oral administration of aqueous extract of lessThan i greaterThan Jussiaea repens L lessThan /i greaterThan may be considered as nontoxic antifertile agent in male rat in a dose dependent manner. NIRMAL KR. PRADHAN , SUBHASISH GHOSAL AND INDRANI CHAKRABORTY Jussiaea repens L , Reproduction, Sperm, Antifertility, Contraceptive. 131-143