Thiocolchicine is against MCF-7, LoVo, LoVo/DX, A-549 and BALB/3T3 cells with IC ₅₀ values of 0.01 μM, 0.021 μM, 0.398 μM, 0.011 μM and 0.114 μM, respectively.Thiocolchicine (1 nM-100 μM; 24-72 hours) shows a relationship between cell cycle blocking activity and growth inhibition in breast cancer cells. It inhibits cell proliferation of MDA-MB-231 and multidrug resistant (MDR) MCF-7 ADRr breast cancer cells with IC ₅₀ s of 0.6 nM and 400 nM, respectively, as well as MDR CEM-VBL leukemia cells (IC ₅₀ =50 nM).