The Northeastern region of India is a repository of medicinal plants, which demand scientific evaluation. Rural populate of Assam had traditionally been practicing some plant formulations though in crude forms for family planning and birth control. The information about plants and herbs and details of methods of crude drug preparation needed scientific investigation. Hence, plants of 41 species belonging to 38 genera and 25 empirical prescriptions were recorded and studied in this project. The herb “Mimosa pudica. Linn” is used by most extensively by the tribal population of Assam for birth control and thus it was studied in detail using white albino mice as reference animal. This study for the first time established scientific knowledge and certain information on indigenous plants and herbs of this region, which are widely used by different population groups of Assam. The results of the present study strongly indicate that the histological, biochemical and physiological changes in Mimosa pudica extract treated mice were due to the presence of some chemical constituents in the plants that could act as an antifertility agent.