: a compound C5H9N3 especially of mammalian tissues that causes dilation of capillaries, contraction of smooth muscle, and stimulation of gastric acid secretion, that is released during allergic reactions, and that is formed by decarboxylation of histidine

Examples of histamine in a Sentence

Recent Examples on the Web
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The theory is that this combination may help keep histamine in check, basically replacing the effect of progesterone. Theara Coleman, TheWeek, 1 July 2026 PureWine removes both the histamines and sulfites that trigger most common wine allergies. ABC News, 29 June 2026 The mushroom also contains immune-modulating polysaccharides that may reduce the over-reactiveness of the immune response and down-regulate histamine levels and inflammation. Samantha Agate, Kansas City Star, 26 June 2026 The center adds that reishi contains immune-modulating polysaccharides that may reduce the over-reactiveness of the immune response and down-regulate histamine levels and inflammation. Samantha Agate, Miami Herald, 26 June 2026 See All Example Sentences for histamine

Word History

Etymology

International Scientific Vocabulary hist- + amine

First Known Use

circa 1913, in the meaning defined above

Time Traveler
The first known use of histamine was circa 1913

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Cite this Entry

“Histamine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/histamine. Accessed 11 Jul. 2026.

Kids Definition

histamine

noun
: a compound that occurs in many animal tissues and plays an important part in allergic reactions (as in hives, asthma, and hay fever)

Medical Definition

: a compound C5H9N3 especially of mammalian tissues that causes dilatation of capillaries, contraction of smooth muscle, and stimulation of gastric acid secretion, that is released during allergic reactions, and that is formed by decarboxylation of histidine

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