It is suggested that gastrointestinal mucosal blood flow depends on a balanced release of vasoactive substances from the endothelium. The present study investigated the effects of molsidomine on the small intestine after ischemia-reperfusion (I/R) injury in four groups of 10 rats each composed: (1) SO, sham operation; (2) untreated I/R; (3) ML, I/R plus molsidomine pretreatment; (4) L-NAME, I/R plus N-omega-nitro-L-arginine methyl ester pretreatment. Intestinal ischemia for 45 min and reperfusion for 60 min were applied. Ileum specimens were obtained to determine the tissue level of malondialdehyde (MDA) and histologic changes. Mean MDA levels in the SO, untreated I/R, ML, and L-NAME groups were 95.60 +/- 2.59, 136.90 +/- 4.35, 121.10 +/- 3.38, and 137.40 +/- 4.42 nmol/g wet tissue, respectively. Although the MDA level in the ML group was higher than in the SO group ( P < 0.0001), it was significantly lower compared to the untreated I/R and L-NAME groups ( P < 0.0001, P < 0.0001). Mucosal injury scores (MIS) in groups 1-4 were 0.2 +/- 0.42, 3.9 +/- 0.73, 1.5 +/- 0.70, and 4.1 +/- 0.56, respectively. In group 3 the MIS was significantly lower than in groups 2 and 4 ( P < 0.0001, P < 0.0001). Molsidomine plays a role in attenuating reperfusion injury of the small intestine by depression of tissue MDA levels and MIS and regulates post-ischemic intestinal perfusion while restoring the intestinal microcirculatory blood flow and histologic injury.