(2-Hydroxy-ethyl)(prop-yl)aza-nium 2-[(2-carboxy-phen-yl)disulfan-yl]benzoate monohydrate.

With the exception of the terminal hydr-oxy group [N-C-C-O = 53.8†(5)°], the cation of the title salt hydrate, C(5)H(14)NO(+)·C(14)H(9)O(4)S(2) (-.)H(2)O, is a straight chain. A twisted conformation is found for the anion [C-S-S-C = -87.44†(16)°]. In the crystal, the anions self-assemble into a helical supra-molecular chain via charge-assisted O-H⋯O(c) hydrogen bonds. These chains are connected into a three-dimensional network via N-H⋯O(c), N-H⋯O(w), O(h)-H⋯O(cb), and O(w)-H⋯O(c) hydrogen-bonding inter-actions (c = carboxyl-ate, w = water, h = hydr-oxy and cb = carbon-yl).