Molecules of the title compound, C15H21N3O3S, have a markedly polarized electronic structure; the carbocyclic ring adopts an envelope conformation and the overall molecular conformation appears to be controlled by two intramolecular hydrogen bonds, one each of the O-H...O and N-H...O types. The molecules are linked into C(6) chains by an intermolecular N-H...O hydrogen bond, and pairs of these hydrogen-bonded chains are linked by a pi-pi stacking interaction.