Background: The licorice (Glycyrrhiza glabra) rhizome has been widely used in traditional medicine for treatment of gastrointestinal diseases.

Objective: In the present study, the effect of hydro-alcoholic extract of licorice rhizome on mechanical activity of isolated ileum of male rats has been studied.

Methods: Seven adult male rats were anesthetized by ethyl ether, their abdomen opened, and ileum dissected and divided into 1 cm segments. The segments were connected to a force transducer longitudinally and inserted to an organ bathe contained oxygenated Tyrode solution (37 °C, pH=7.4). Their mechanical activity of ileum was recorded by power lab AD instrument in basal condition, and after administration of L-NAME (10^-4M) drug in the presence and absence of licorice rhizome extract (0.0175 mg/ml). Also the mechanical activity of control group segments were recorded at the same condition with extract solvent (ethanol %70).

Results: A significant decrease in mechanical activity of the isolated ileum occurred after administration of hydro-alcoholic extract of licorice compared to the control group, while the mechanical activity of ileum tissue not significantly changed in the coadministration of L-NAME and extract between experimental and control groups.

Conclusion: We can conclude that hydro-alcoholic extract of licorice has modifying effect on ileum motility, and this activity may be occurred independently to the nitrergic system.