Definition of histamine in US English:



  • A compound which is released by cells in response to injury and in allergic and inflammatory reactions, causing contraction of smooth muscle and dilation of capillaries.

    A heterocyclic amine; chemical formula: C₅H₉N₃

    • ‘Opioids can cause itching, by releasing histamine from mast cells.’
    • ‘In anaphylactic reactions it does switch off the cells that are releasing histamine…’
    • ‘Quercetin reduces histamine degranulation and the subsequent release of histamine and inflammatory leukotrienes.’
    • ‘Allergic reactions involve the release of histamine, a chemical that triggers inflammation and swelling.’
    • ‘The allergic reaction causes the cells to release histamine, a chemical which prompts the sneezing and itching impulse.’


Early 20th century: blend of histidine and amine.