Benzoxazole derivatives and drugs containing the same as the active ingredient

1 2 3 A compound represented by the following general formula (1): wherein Rrepresents a halogen atom, Rrepresents hydrogen atom or a lower alkyl group, and Rrepresents hydrogen atom, a lower alkyl group, a lower alkoxyl group, a hydroxy lower alkyl group, a halogen atom, or a substituted or unsubstituted amino group, wherein a substituent on the amino group is selected from the group consisting of a lower alkyl group, a lower alkenyl group, a lower alkylcarbonyl group, and an amino protective group, or a salt thereof. The compound of the present invention or a salt thereof is useful as an active ingredient of medicaments for preventive and/or therapeutic treatment of conditions of irritable bowel syndrome and digestive tract functional disorder, or condition of diarrhea.