 Chronic renal insufficiency is a common and important health problem that causes morbidity and mortality among patients who have undergone liver transplantation. It is mainly caused by drugs calcineurin inhibitors that are used to prevent or treat rejection and once established, there is no effective treatment. This research investigates whether L-arginine can reverse the effects of calcineurin inhibitors on the kidneys and thus prevent renal insufficiency in liver transplant recipients. 