Mycophenolate mofetil is the generic name for the drug Cellcept. Cellcept is an immunosuppressant medication that is used to prevent organ rejection in patients who have received a kidney, heart, or liver transplant. It works by suppressing the body's immune system, which helps to prevent the immune system from attacking the transplanted organ. Mycophenolate mofetil is commonly prescribed in combination with other medications to help prevent rejection and improve the success of organ transplantation.