An object of the present invention is to provide a method for encapsulating a poorly water-soluble pharmacologically active substance in a liposome with high efficiency. The present invention provides a composition comprising a lipid having a phosphatidylcholine group, a cholesterol compound, a lipid having a phosphatidylethanolamine group, and a poorly water-soluble pharmacologically active substance, wherein the molar ratio of the lipid having a phosphatidylcholine group, the cholesterol compound, the lipid having a phosphatidylethanolamine group, and the poorly water-soluble pharmacologically active substance is 3 to 8:2 to 7:0.1 to 3:0.001 to 5, respectively.
