The present invention provides a pharmaceutical composition which can permit a sparingly water-soluble drug substance to be solubilized or dispersed in a pharmaceutically allowable liquid medium (e.g., fat emulsion, etc.), characterized in that said pharmaceutical composition contains (a) a base (e.g., polyethylene glycol, etc.), (b) a sparingly water-soluble drug substance and (c) a fatty acid or its pharmaceutically allowable salt. The pharmaceutical composition can be mixed with a pharmaceutically allowable liquid medium to produce a pharmaceutical preparation for administration, such as an injectable solution, etc., wherein mixing can be performed for a shortened period of time and the sparingly water-soluble drug substance can be uniformly solubilized or dispersed in a liquid medium.