6-Thioguanosine is a purine analog that is used in the treatment of skin cancer and bowel disease. It has been shown to be an inhibitor of leukemia cells and also inhibits the growth of colon cancer cells. 6-Thioguanosine binds to the rate constant for uridine phosphorylation, which prevents the production of DNA. This drug also has an anti-inflammatory effect on bowel disease, which may be due to its ability to inhibit bcl-2 protein expression. 6-Thioguanosine is a fluorescent derivative that can be used as a substrate for x-ray diffraction data or as a biological sample in biological studies.