A composition containing an extremely poorly water-soluble drug and obtained by treating, with a supercritical fluid or subcritical fluid of carbon dioxide, a mixture comprising a porous silica material and the extremely poorly water-soluble drug; and its production process. The porous silica material has an average pore diameter in a range of from 1 to 20 nm, pores having diameters within .+-.40% of the average pore size account for at least 60% of a total pore volume of the porous silica material, and in X-ray diffractometry, the porous silica material has at least one peak at a position of diffraction angle (2.theta.) corresponding to a d value of at least 1 nm. The composition according to the present invention, which contains the extremely poorly water-soluble drug, is excellent in the dissolution of the extremely poorly water-soluble drug.