Aqueous Garlic Extract (AGE) has previously been shown to have relaxant effects on isolated rat aorta rings (1). Several studies have suggested the relaxant effect was mediated by endothelial nitric oxide and vasodilator prostaglandins (2). The aim of the present study was to investigate the effect of fresh AGE on phenylephrine-induced contractile responses. 1g fresh garlic was squeezed and extracted in 10ml distilled water for the stock solution. Further dilutions were also prepared by distilled water. Briefly, corpus cavernosum strips were suspended in oxygenated Krebs buffer at 37C and isometric contractions to phenylephrine (10-5M) were recorded and AGE extract was added to the bath cumulatively to maintain increasing concentrations of 150 μg/ml, 300 μg/ml, 450 μg/ml and 600 μg/ml. Then the tissue was washed out twice and pretreated L-NAME (10-5M) or indometasine (10-3M) or both. The increasing concentrations of AGE produced a relaxation on corpus caverosum tissues which were contracted by phenylephrine. The relaxant responses were partially blocked by L-NAME preincubation, but not indometasine preincubation demonstrating that the relaxant effect of AGE on corpus cavernousum tissue was partially mediated by NO.