8-Hy-droxy-5-(hy-droxy-meth-yl)quinolin-1-ium chloride.

The title compound, C(10)H(10)NO(2) (+)·Cl(-), contains a quinoline ring system which is essentially planar, with the largest deviation from the mean plane being 0.017 (1) Å. In the crystal, the ion pairs and their inversion-symmetry-related partners are linked by N-H⋯Cl and O-H⋯Cl hydrogen bonds to form tetramers which are further connected through O-H⋯O hydrogen bonds, building infinite one-dimensional chains parallel to the [010] direction.