The Brain Natriuretic of Peptide (BNP) is a hormone, which becomes with heart achievement weakness (heart insufficiency) in the left Herzkammer formed and seperate (sezerniert). It received its names by the discovery in the pig brain and was found in small quantity also in the human brain. Its characteristic is primarily a pre and a rereading lowering. Additionally it works in the kidneys, where it promotes the sodium (natriuretisch) and the urine elimination (diuretisch). The height of the BNP concentration in the blood correlates well with the severity level of heart achievement weakness: The more highly the value, the more weakly the heart. At present there are first investigations to the possible employment of artificially manufactured BNP with patients with acute and chronic heart insufficiency.