Histamine (combining the Greek "histos" = tissue and "amin" = nitrogenous compound) is a natural substance, which fulfils important regulatory and mediatory functions in animal organisms, and is also frequently found in bacteria and in the plant kingdoms. Biochemically, histamine belongs to the group of biogenic amines. In its purest form, histamine is a white solid material with a molar mass of 111.15 g/mol. Histamine is easily soluble in water and ethanol, but badly dissolved in diethyl ether, which indicates that it has also bad solubility in fat.