Mizoribine is primarily used as an immunosuppressive agent in the field of medicine. It is commonly prescribed to prevent organ rejection in patients who have undergone kidney transplants. The drug works by inhibiting the proliferation of lymphocytes, which are crucial in the immune response, thereby reducing the risk of the body attacking the transplanted organ. In addition to its use in transplant medicine, Mizoribine is also employed in the treatment of autoimmune diseases such as lupus nephritis and rheumatoid arthritis. By suppressing the overactive immune system, it helps to alleviate symptoms and slow the progression of these conditions. The drug is administered orally and is often used in combination with other immunosuppressive agents to enhance its efficacy and minimize potential side effects. Regular monitoring of blood levels and kidney function is essential to ensure the safe and effective use of Mizoribine in patients.