121 JOURNAL OF NATURAL REMEDIES 1. Introduction In search of antifertility agents from plant origin, indigenous to India, two plants were selected from the literature [1, 2], namely Artabotrys odoratissimus Roxb. (Annonaceae) and Couroupita guianensis Aubl. [3]. A. odoratissimus, (Synonym: A. Hexapetalus ) is locally known as Nag Champa [4] and was identified as a potential antifertility agent [5]. In India it is known for its antifertility effect [6]. Literature survey revealed that systematic *Corresponding author E-Mail address: mbs_mg@yahoo.co.in study on this plant for the antifertility activity is still lacking. C. guianensis Aubl. is widely planted for its ornamental value. It is known as cannon ball tree in English and Kailaspati in Hindi and it belongs to the family Lecythidaceace [3,7]. The petroleum ether and methanol extracts of aerial parts were reported to possess antibacterial, antimalarial and anthelmintic activity [8]. The aqueous extract of the flower Antifertility activity of Artabotrys odoratissimus Roxb. and Couroupita guianensis Aubl. M. Geetha*, M. B. Shankar, R. S. Mehta, A. K. Saluja A.R. College of Pharmacy and G. H. Patel Institute of Pharmacy, PO Box No. 19, Vallabh Vidyanagar, Gujarat 388 120. India Abstract Objective: To study antifertility activity of various extracts of A. odoratissimus Roxb. and C. guianensis Aubl. Materials and methods: Antifertility activity of benzene, ethanol and water extracts of leaves of A. odoratissimus and bark and flowers of C. guianensis was studied for their effect on duration of various stages of oestrus cycle in adult female rats and on the number implantation sites in the pregnant rats. Results: All the extracts of A. odoratissimus leaf and ethanol and water extracts of C. guianensis bark and flower showed significant prolongation of dioestrus stage (p<0.05). Ethanol and water extracts of A. odoratissimus leaf showed anti-implantation effect. Ethanol extract of C. guianensis bark and all the extracts of its flower reduced the number of implantations. Conclusion: The disturbances in the reproductive cycle indicate effect of these plants on the sex hormones in the animals. Prevention of implantation may be due their interference in the receptive stage of the uteri and endometrial sensitivity for decidualisation. The results suggest that the both plants are having antifertility activity and possible therapeutic use. Vol 5/2 (2005) 121 - 125