Evaluation of in-vivo antidiarrheal activities of 80% methanol extract and solvent fractions of the leaves of Myrtus communis Linn (Myrtaceae) in micernMekonnen SisayrnAddis Ababa University, 2015rnMyrtus communis L. has a folkloric repute for the management of diarrhea and dysentery in different parts of the world including Ethiopia. However, it has not been scientifically validated yet regarding its safety and efficacy. The aim of this study was to investigate the antidiarrheal effects of both 80% methanol extract (80ME) and solvent fractions of the leaves of Myrtus communis L in mice models of diarrhea. The 80ME was obtained using maceration technique. Besides, the fractions were prepared from the leaf powder by successive soxhlet extraction with solvents of increasing polarity (chloroform followed by methanol) and then maceration of the marc of the methanol fraction with distilled water. The antidiarrheal activities of the 80ME as well as solvent fractions were evaluated using castor oil induced diarrhea, intestinal transit and enteropooling models in mice. For the 80ME, Group I served as negative control and received 10 ml/kg of distilled water orally; Group II served as a positive control and given a standard drug (3 mg/kg loperamide orally); Group III-V were test groups and received 100, 200 and 400 mg/kg of the extract respectively. A similar grouping was used for the fractions, except for the aqueous group , where they received 200, 300, 400 mg/kg with an additional dose of 800 mg/kg. In the castor oil induced diarrheal model, the 80ME significantly delayed the diarrheal onset at 200 mg/kg (p