6-Mercaptopurine riboside is primarily used in the treatment of acute lymphoblastic leukemia (ALL) and other types of cancers, including chronic myeloid leukemia (CML) and non-Hodgkin's lymphoma. It functions as an antimetabolite, interfering with the synthesis of nucleic acids, thereby inhibiting the growth of cancer cells.

In addition to its anticancer properties, it is also employed as an immunosuppressive agent in organ transplantation to prevent rejection. It helps in reducing the activity of the immune system, making it less likely to attack the transplanted organ.

Furthermore, it is used in the management of autoimmune diseases such as Crohn's disease and ulcerative colitis. By suppressing the immune response, it helps in controlling the inflammation and symptoms associated with these conditions.

The compound is often administered orally or intravenously, and its dosage is carefully monitored to balance efficacy with potential side effects, such as bone marrow suppression and liver toxicity. Regular blood tests are typically required to ensure safe and effective use.