6-Thioguanine is primarily used in the treatment of certain types of cancer, particularly acute leukemia. It functions as an antimetabolite, interfering with the synthesis of DNA and RNA, which helps to slow or stop the growth of cancer cells. This makes it a crucial component in chemotherapy regimens for managing leukemia and other malignancies.

In addition to its role in cancer therapy, 6-Thioguanine is also utilized in the treatment of inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis. It works by suppressing the immune system, thereby reducing inflammation and providing relief from symptoms. This application is particularly beneficial for patients who do not respond well to other forms of treatment.

The drug is administered orally and requires careful monitoring by healthcare professionals to manage potential side effects, which can include bone marrow suppression and liver toxicity. Regular blood tests are often necessary to ensure the patient's safety and to adjust the dosage as needed.

Overall, 6-Thioguanine plays a significant role in both oncology and gastroenterology, offering therapeutic benefits for patients with specific types of cancer and chronic inflammatory conditions.