In the zwitterionic title compound, C9H15NO4, the piperidinium N atom is protonated and the OH group of one of the carboxylate groups is deprotonated. The piperidinium ring adopts a chair conformation. In the crystal, N—H...O and O—H...O hydrogen bonds generate an R33(15) ring motif and link the molecules into infinite chains propagating along [010]. The structure is further consolidated by weak C—H...O interactions to form a three-dimensional network.
