Mycophenolate mofetil is primarily used as an immunosuppressive medication. It is commonly prescribed to prevent organ rejection in patients who have undergone kidney, heart, or liver transplants. The drug works by inhibiting the proliferation of T and B lymphocytes, which are crucial in the immune response, thereby reducing the risk of the body attacking the transplanted organ.

In addition to transplant patients, mycophenolate mofetil is also used in the treatment of certain autoimmune diseases, such as lupus and rheumatoid arthritis. In these conditions, it helps to control the overactive immune system, thereby reducing inflammation and preventing damage to tissues and organs.

The medication is often used in combination with other immunosuppressive drugs to enhance its effectiveness and to allow for lower doses of each drug, minimizing potential side effects. It is available in oral and intravenous forms, providing flexibility in administration based on patient needs and medical conditions.