C12H12O3, Mr = 204.2, monoclinic, P2(1)/c, a = 11.815 (2), b = 7.673 (2), c = 12.580 (3) A, beta = 115.06 (2) degree, V = 1033.1 (9) A3, Z = 4, Dx = 1.313 g cm-3, lambda (Cu K alpha) = 1.54184 A, mu = 7.34 cm-1, F(000) = 432, T = 299 K, R = 0.065 for 1420 observations (of 2131 unique data). The stereochemistry of the hydroxyl and hydroperoxyl groups is cis. The hydroperoxyl O-O bond distance is 1.476 (2) A. The hydrogen-bonding pattern consists of two intermolecular interactions: a hydroperoxyl donor to the hydroxyl group, with an O...O distance of 2.818 (2) A and an O-H...O angle of 168 (2) degree, and a hydroxyl donor to O(3) of the hydroperoxyl group, with a distance and angle of 2.670 (2) A and 170 (2) degree, respectively.