The influence of Ocimum sanctum Linn. leaf extract on some biochemical parameters with reference to antifertility potential in female albino rats. The healthy female albino rats were administered with Ocimum sanctum Linn. leaf extract orally at different dose (100, 200, 300mg/kg body weight/15days) and duration (300mg/kg body weight/30days). The total proteins, total carbohydrates, total lipids, cholesterol, phospholipids and triglycerides were estimated using standard biochemical methods in control and experimental female albino rat tissues like ovary, uterus, vagina, liver and plasma.The ovarian and uterine lipids were enhanced as the dose and duration of the extract increases. The elevated cholesterol levels observed in ovary and uterus but at higher and prolonged dose and duration uterine cholesterol levels were depleted. The enhanced phospholipids can be correlated to decreased oxidative metabolism owing to low level of estrogen in circulation. On the basis of these observations it may be concluded that the extract of Ocimum sanctum leaf at higher dose and prolonged duration owing to its potent antiestrogenic nature and alters the biochemical milieu of the reproductive tract.