The present invention provides an aqueous composition obtained by dissolving, in water, hydroxyethyl cellulose, methyl cellulose and/or Hypromelose and the invention also provides a medicament comprising the aqueous composition and a drug incorporated therein. The viscosity of the composition of the present invention is abruptly increased when heated at a temperature near the body temperature, but it is rapidly reduced when applying weak force thereto, for instance, by lightly shaking the same. When the medicament obtained by incorporating a drug into the composition of the present invention is administered to a living body, the composition of the present invention can be thickened without delay at the administered site and thus stay at that site over a long period of time and this in turn leads to a considerable increase of the BA of the drug. In addition, the thermally thickened composition of the present invention can easily be converted into a composition having a high flow ability simply by applying weak force to the composition and therefore, the composition of the invention is not necessarily stored at a cold place or in a refrigerator and it is convenient to carry about.
