An appetite-stimulating agent and a therapeutic agent for anorexia, each comprising, as an active ingredient, a sulfonamide derivative or sulfonic acid ester derivative represented by the following general formula (I): ##STR00001## wherein the ring A represents a monocyclic or bicyclic aromatic ring which may be substituted, the ring B represents a 6-membered unsaturated hydrocarbon ring or a 6-membered unsaturated heterocyclic ring containing one nitrogen atom as a heteroatom, each of which may be substituted, the ring C represents a 5-membered heterocyclic ring containing one or two nitrogen atoms, which may be substituted, W represents a single bond or --CH.dbd.CH--, X represents --N(R.sup.1)-- or an oxygen atom, Y represents a carbon atom or a nitrogen atom, Z represents --N(R.sup.2)-- or a nitrogen atom, and R.sup.1 and R.sup.2 may be identical or different and each represents a hydrogen atom or a lower alkyl group, or a pharmacologically acceptable salt thereof, or a hydrate thereof.
