N'-(3,4-Dihydroxy-benzyl-idene)acetohydrazide monohydrate.

In the title compound, C9H10N2O3·H2O, the Schiff base mol­ecule is approximately planar, the dihedral angle between the benzene and acetohydrazide planes being 5.40 (7)°. An intra­molecular O—H⋯O hydrogen bond is observed. In the crystal, mol­ecules are linked into a two-dimensional network parallel to (100) by O—H⋯O, N—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds, and by π–π inter­actions between symmetry-related benzene rings [centroid–centroid distance = 3.543 (2) A].