The role of selenium (Se) supplementation on glutathione, a potent intracellular redox buffer, and trehalose, a well-known stress protectant molecule, was studied. The amount of glutathione decreased significantly while that of trehalose showed a minor decrease in the cells grown in Se-supplemented medium. After heat shock, glutathione content diminished further, whereas that of trehalose increased significantly in control and Se-supplemented cells. These findings suggest the importance of trehalose as an antioxidant molecule.