The object of the present invention is to provide a polyamine composition, derived from plant material, having low salt concentration, and a method for preparing a polyamine composition in high production efficiency.A method for preparing a polyamine composition of the present invention is characterized by comprising step (1) of treating a plant and/or a processed plant product with ethanol step (2) of treating a plant and/or a processed plant product with water step (3) of treating a plant and/or a processed plant product under acidic conditions and step (4) of separating and extracting a liquid fraction.本發明之目的係提供鹽濃度低的源自植物原料之多胺組成物、及一種生產效率良好的製造多胺組成物之方法。本發明之多胺組成物之製造方法的特徵係包括:(1)以乙醇處理植物及/或植物加工物之步驟、(2)以水處理植物及/或植物加工物之步驟、(3)在酸性條件下處理植物及/或植物加工物之步驟、及(4)分離並提取液體部分之步驟。
