The invention provides application of a triterpenoid saponin compound to the preparation of an anti-pathogeny microorganism medicament, particularly provides to application of the triterpenoid saponin compound to the preparation of anti-tuberculosis and anti-leprosy medicaments. The triterpenoid saponin compound is a triterpenoid saponin compound shown as a chemical formula in the specifications. In the chemical formula, any two of R1, R2 and R3 refer to methyl and the other refers to a hydrogen atom R4 refers to pentatomic or hexahydric monosaccharide or disaccharide formed by the pentatomic or hexahydric monosaccharide or glycosyl formed by an aldehyde acid derivative of the monosaccharide or the disaccharide and R5 refers to a hydrogen atom or pentatomic or hexahydric monosaccharide or disaccharide formed by the pentatomic or hexahydric monosaccharide or a substituent group formed by an aldehyde acid derivative of the monosaccharide or the disaccharide. According to the invention, a medicament with a remarkable anti-pathogeny microorganism effect is provided.
