Thiocolchicoside (THC) is an important active pharmaceutical ingredient (API) used as a muscle relaxant because of its anti-inflammatory and analgesic effects. The only entry for a THC-related compound present in the Cambridge Structural Database (CSD) corresponds to a THC ethanol solvate hydrate (refcode: THCLCS). The diffraction pattern recorded for the THC raw material (C 27 H 33 NO 10 S· x H 2 O) is different from the pattern calculated using the THCLCS crystallographic data contained in the CSD. The indexing of the THC raw material pattern, produced an orthorhombic unit cell with a = 28.018(7) Å, b = 12.519(2) Å, c = 8.519(1) Å, and V = 2988.01 Å 3 . All the diffraction maxima of the powder pattern of a phase recrystallized in water (C 27 H 33 NO 10 S·2H 2 O) can be indexed in an orthorhombic cell with a = 25.264(4) Å, b = 13.537(3) Å, c = 8.553(1) Å, and V = 2925.12 Å 3 . Thermogravimetric analysis shows that this compound is a dihydrate phase. Upon heating, a new anhydrous phase (C 27 H 33 NO 10 S) with a monoclinic cell and unit cell parameters: a = 17.090(5) Å, b = 19.485(5) Å, c = 8.526(3) Å, β = 100.30(2)°, and V = 2793.34 Å 3 is obtained.