Histamine is a biogenic amine which is formed by enzymatical decarboxylation from the amino acid histidine. It can enter the human digestive system via food consumption and trigger numerous intolerance related symptoms. The extent of the reaction depends on the ingested amount of histamine.
Furthermore, toxic reactions are possible after uptake of high histamine concentrations. These result from bacterial degradation of protein-rich food like fish, cheese and meat as well as from red wine consumption. The concentration of histamine formed depends on the bacterial species, temperature and exposure time.