The present invention relates to a new pharmaceutical use as acceptable salt ethylamino benzoic acid derivative or a pharmaceutically.ethyl-amino-acid derivatives, 2-acetoxy-5- [2- (4-trifluoromethyl-phenyl) -ethyl] -benzoic acid, 2-hydroxy-5- [2- (4-trifluoromethyl Romero butyl-phenyl) -ethyl] -benzoic acid, pain본 발명은 에틸아미노 벤조산 유도체 또는 이의 약학적으로 허용가능한 염의 신규 의약 용도에 관한 것이다.