1-Methylhistamine also known as tele-methylhistamine can be found primarily in most biofluids, including cerebrospinal fluid (CSF), urine, feces, and blood, as well as in human bone marrow, brain, and mast cell tissues; it is involved in histidine metabolism. This endogenous compound can be a marker of the inflammatory bowel disease because during the development of the disease it concentration is enhanced. Besides, experiments on dogs have revealed, that 1-methylhistamine can be used as a marker of intestinal inflammation in chronic gastrointestinal disease.

Histamine is a depressor amine derived by enzymatic decarboxylation of histidine. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and a centrally acting neurotransmitter. Phosphate salt of jistamine was used as a diagnostic aid for evaluation of gastric acid secretory function. In addition, this compound is used as a positive control in evaluation of allergenic (immediate hypersensitivity or "Type I") skin testing. In addition, histamine is being studied for treatment of multiple sclerosis. It was approved, that histamine physiological functions are mediated by four 7-transmembrane G protein-coupled receptors (H1R, H2R, H3R, H4R) that are all targets of pharmacological intervention. The receptors display molecular heterogeneity and constitutive activity. H1R antagonists are long known antiallergic and sedating drugs, whereas the H2R led to the development of H2R-antagonists that revolutionized stomach ulcer treatment. The H3R is an auto receptor and heteroreceptor providing negative feedback on histaminergic and inhibition on other neurons. The H4R occurs on immuncompetent cells and the development of anti-inflammatory drugs is anticipated.