Objectives : Albizzia Julibrissin was formulated to contain various natural products known to cure erectile dysfunction. This study was aimed to investigate the effects of Albizzia Julibrissin on the nitric oxide synthase (NOS) activity, nitrite level, antioxidation and erectile responses induced by ethanol in corpus cavernosum penis of rats. Methods : The crushed Albizzia Julibrissin was extracted 3 times, each time with 3 volumes of methyl alcohol at $60^{circ}C$ for 24 h. The extract was filtered and evaporated under a reduced pressure using a rotary evaporator to yield 45.3 g. Albizzia Julibrissin extract was oral-administered 100 mg per 1 kg of body weight for 20 days, while the normal group was administered only with a saline. The efficacy of Albizzia Julibrissin against erectile function was examined as described in the text. Results : The level of urethral NOS activity and nitrite were increased by Albizzia Julibrissin. The level of lipid peroxide was decreased by Albizzia Julibrissin. The level of urethral lipid peroxide in the ethanol-Albizzia Julibrissin double administered rats was decreased as low as in the norma! group, while the one in the ethanol-treated group was increased. The level of urethral nitrite, NOS activity, glutathione and serum testosterone in the ethanol-Albizzia Julibrissin double administered rats were as high as in the normal group, while the one in the ethanol-treated group was decreased. The erectile response to cavernous nerve stimulation in the ethanol-Albizzia Julibrissin double administered rats increased as high as in the normal group while the one in the ethanol-treated group decreased. Conclusions : Albizzia Julibrissin was shown to be effective for the treatment of erectile dysfunction induced by ethanol in rats.