Colchicine is a drug used for the treatment of FMF, primary biliary cirrhosis, psoriasis, Behçet's disease, aphthous stomatitis. Glutathione reductase (GR; E.C 1.6.4.2) is a crucial enzyme which reduces glutathione disulphide to the sulfhydryl form GSH by the NADPH-dependent reduction, which is an important cellular antioxidant system. The purpose of the present work is to evaluate the in vitro effects of colchicine on GR from various sources. The component of glutathione redox cycle, GR, plays important role in the protection of the cell from the toxic effects of reactive oxygen species. Due to its significance the enzyme has been purified from a number of animals, plants and microbial sources and studied the in vitro effects of many chemical compounds or drugs on enzyme activity. We have established that colchicine inhibits GR in a concentration dependent manner. We have investigated the kinetic characterization, inhibition types and constants (Ki).