Histamine is one of the biogenic amines. It arises as a breakdown product from the amino acid histidine, but bacteria can also break down histidine into histamine. Histamine is therefore also absorbed through food, especially through foods that are ripened or prepared by bacteria (e.g. mature cheese, wine, sauerkraut). Histamine is a natural messenger substance. On the one hand, it is formed by the body itself and can be found in the entire organism. From a biochemical point of view, histamine is one of the biogenic amines. This is the name given to chemical compounds that arise from ammonia; for example, the amino acids from which proteins are built. In the human organism, histamine is involved in many different body functions. For example, it plays an active role in the immune system. If a part of the body swells due to an injury, this is due to the effects of histamine. Histamine is also involved in the development of itching and pain - and in many allergic reactions. Histamine is a natural substance that acts as a tissue hormone and neurotransmitter in the human or animal organism. It is also widespread in the plant kingdom as well as in bacteria. In humans and other mammals, histamine plays a central role in allergic reactions. It is involved in the immune reaction, i.e. in the defense against foreign substances. It serves as one of the messenger substances in the inflammatory reaction. Here it causes the tissue to swell. Histamine is an important regulator in numerous processes in the body. In the gastrointestinal tract, it acts to regulate gastric acid production and motility. In the central nervous system, it supports the control of the sleep-wake rhythm and appetite control. Biochemically, histamine is a biogenic amine, like tyramine, serotonin, dopamine, adrenaline, Norepinephrine or octopamine. It is formed by splitting off carbon dioxide from the amino acid histidine. Histamine is particularly stored in mast cells, in some of the white blood cells and in nerve cells.