Clinical and experimental studies indicate that angiotensin II (A II) is involved in the process of tissue destruction in chronic renal diseases. Since the recognition of its potent vasoconstrictor action in the renal circulation. A II has several times come into the forefront in the scientists by revealing new biological actions which are apparently unrelated to any of its previously recognised actions. Many of these actions have now been extensively studied. Of interest, also, are its non-renal actions which are now known to be similarly rich in variety, due to extensive investigations on the central nervous and other organ systems.