An effective and simple process for producing a fine dispersion of a poorly soluble drug and a fine sparingly-soluble-drug dispersion having excellent dispersion stability. In a first step, a poorly soluble drug is suspended in a liquid containing no deflocculant and the suspension is subjected to a high-pressure treatment with a high-pressure homogenizer. In a second step, a deflocculant is added to the dispersion obtained in the first step and this dispersion is subjected to a deagglomeration treatment such as a high-pressure treatment with a high-pressure homogenizer or an ultrasonic treatment. Thus, a fine dispersion of the poorly soluble drug is effectively and simply produced in which the size of the particles dispersed is on the order of nanometer. The fine sparingly-soluble-drug dispersion produced has excellent dispersion stability and the fine particles of the poorly soluble drug do not suffer aggregation/sedimentation even upon standing. Also provided is an excellent medicinal preparation reduced in the content of contaminants. It is obtained from the thus-produced fine dispersion of the poorly soluble drug.
