Abstract: There are provided acetamide compounds represented by the following formula; ##STR1## wherein R.sub.1 and R.sub.2 each independently represents a hydrogen atom, a C.sub.1 to C.sub.6 straight- or branched-chain alkyl or alkenyl group, a C.sub.3 to C.sub.6 cycloalkyl or cycloalkenyl group, or a C.sub.6 to C.sub.10 aromatic group; or R.sub.1 and R.sub.2 combine with each other in combination with the adjacent N and carbon atoms or further with at least one of nitrogen, oxygen and sulfur atoms to represent a 5- to 6-membered heterocyclic ring group; R.sub.3 represents hydrogen atom, a C.sub.1 to C.sub.6 straight- or branched-chain alkyl or alkenyl group, a C.sub.3 to C.sub.6 cycloalkyl or cycloalkenyl group, a halogen atom, a C.sub.1 to C.sub.6 straight- or branched-chain alkyloxy group, or a C.sub.3 to C.sub.6 cycloalkyloxy or cycloalkenyloxy group; and n is an integer of 1 to 4, and their pharmaceutically acceptable salts.