Abstract: A surface active material may be produced from the lung tissue of mammal by means of employing an acetone-treatment procedure as well as an organic solvents mixture-treatment procedure other than the conventional procedures of differential centrifugation, density gradient centrifugation and dialysis. The chemical composition of the active material has for example, a phospholipid content of 75.0-95.5%, a neutral lipid content of 1.8-14.0%, total cholesterol content of 0.0-3.0%, carbohydrate content is 0.1-1.5% and protein content is 0.5-5.0%, all based on the dried weight of the material. The pharmaceutical composition containing the surface active material defined as above is usable for clinical treatment of human hyaline-membrane disease.