Sildenafil is used for the treatment of erectile dysfunction and is helping millions of men around the world to achieve and maintain a long lasting erection. Fifty healthy male rabbits (Oryctolagus cuniculus) were used in the present study and exposed daily to sildenafil (0, 1, 3, 6, 9mg/kg) for 5 days per week for 7 weeks to investigate the biochemical changes and alterations in the hepatic tissues induced by this drug overdosing.