RESUMEN
<p><b>OBJECTIVE</b>To compare the anti-fertility effects of the four extracts from the roots of Rhynchosia volubilis Lour on male mice, that is, ethanolic extract, ethyl acetate extract, n-butanol extract and aqueous extract.</p><p><b>METHODS</b>Four extracts from the roots of Rhynchosia volubilis Lour (1%, 0.1 ml/10 g), were administered orally for 11 weeks to adult male mice. The fertility and testicular function of the mice were assessed by mating tests and analyses of sperm motility in cauda epididymides and biochemical and histological indexes in the blood samples and reproductive organs.</p><p><b>RESULTS</b>The four extracts, especially aqueous extract, gradually decreased the pregnancy rate of the experimental mice from the 77th day of the treatment, with an obvious reduction in the number of spermatozoa. Morphological observation of the reproductive organs by light microscopy showed that the numbers of the secondary spermatocytes and spermatids were decreased in varied degrees, and the seminiferous tubules were disarranged, while the numbers and shapes of and spermatids were decreased in varied degrees, and the seminiferous tubules were disarranged, while the numbers and shapes of spermatogonia, Sertoli cells and Leydig cells remained unchanged.</p><p><b>CONCLUSION</b>The four extracts from the roots of Rhynchosia volubilis Lour all have anti-fertility effects on male mice, and that of the aqueous extract is more obvious.</p>