Glutathione plays an important cytoprotective role in the gut. Animal studies have demonstrated that the provisions of glutathione precursors are protective for different types of free-radical-mediated cellular injury. There is a need to clarify the potential role of glutathione supplementation in ischemia-reperfusion injury and inflammatory bowel disease. More speculative is whether treatment with glutathione precursors can modify the progress of colorectal cancer.