Abstract: Tetrahydroimidazopyridine derivatives which are useful for the treatment of irritable bowel syndrome are provided and can be represented by the following formula, ##STR1## wherein either one of X and Y is nitrogen and the other one is a radical represented by the formula .dbd.C(R.sup.1)--; and R is a radical of the formula ##STR2## a radical of the formula ##STR3## or a radical of the formula ##STR4## in which R.sup.1, R.sup.2 and R.sup.3 are same or different and represent hydrogen or a C.sub.1 -C.sub.6 alkyl group, and salts thereof. Pharmaceutical compositions are also provided.

Abstract: 4,5,6,7-Tetrahydrobenzimidazole derivatives represented by general formula (I) ##STR1## wherein groups represents the following: R.sup.1, R.sup.2, R.sup.3 : independently represent hydrogen atom, hydroxy group, a halogen atom, a lower alkyl group which may optionally be substituted with a halogen atom, a lower alkoxy group, a lower alkylthio group, an aralkyloxy group, an aryloxy group, a lower alkanoyl group, carboxy group, a lower alkoxycarbonyl group or nitro group;R.sup.4, R.sup.5, R.sup.6 : hydrogen atom or a lower alkyl group;X: oxygen atom or sulfur atom;or salts thereof which are believed to have a 5-HT.sub.3 antagonizing activity.