Modigraf, known generically as tacrolimus, is a potent immunosuppressive medication primarily used to prevent organ rejection in patients who have undergone solid organ transplantation, such as a liver, kidney, or heart transplant. It functions by inhibiting the activity of T-lymphocytes, a type of white blood cell that plays a significant role in the body's immune response, thereby reducing the immune system's ability to attack the transplanted organ. Modigraf is available in granule form for oral suspension and as capsules, allowing for flexible dosing tailored to the specific needs of the patient. It is crucial for patients taking Modigraf to adhere closely to their prescribed regimen and to undergo regular monitoring by their healthcare provider to manage potential side effects and ensure the optimal balance between preventing rejection and minimizing adverse effects.