Yohimbine (0. 5~4mg ? kg-1, sc) and idazoxan (2~8 mg ? kg-1,sc) showed a dose related antagonistic action on the inhibitory effect of xylazine (4mg ? kg-1,sc) on the gastrointestinal propulsive motility in mice. Xylazine (2mg,4mg ? kg-1,sc),clonidine(120 ?g ? kg-1,sc) exhibited the inhibitory effect of gastrointestinal basic electrical rhythm on the stomach, duodenum, jejunum and ileum in rats.The inhibitory effects of these drugs were the strongest at 30 min after administration of Compounds. Yohimibine (4mg ? kg-1,sc) was found to antagonize the inhibitory effect of xylazine (4mg ? kg-1,sc) on the gastrointestinal basic electrical Rhythm.