histamine
noun
his·ta·mine
ˈhi-stə-ˌmēn 
-mən
-mən
: 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
Antihistamines work by defanging histamine, the main chemical responsible for the miserable milieu of allergy symptoms.
—
Erica Sloan, SELF, 2 Apr. 2025
And that then triggers these cells, called the mast cells, to release all these inflammatory mediators, like histamine and other kinds of mediators, like nutrients, which can have kind of profound effects.
—Ron Estes, MSNBC Newsweek, 28 Mar. 2025
In systemic mastocytosis, low blood pressure happens because the chemicals released by extra mast cells, like histamine, cause blood vessels to widen and relax.
—Sarah Jividen, Verywell Health, 15 July 2024
Seasonal allergies are the body’s response to pollen from trees and grass; the immune system releases chemicals, like histamines, leukotrienes, and prostaglandins, which cause all those uncomfortable, familiar symptoms.
—Allie Volpe, Vox, 7 Dec. 2018
See All Example Sentences for histamine
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Erica Sloan, SELF, 2 Apr. 2025
And that then triggers these cells, called the mast cells, to release all these inflammatory mediators, like histamine and other kinds of mediators, like nutrients, which can have kind of profound effects.
—Ron Estes, MSNBC Newsweek, 28 Mar. 2025
In systemic mastocytosis, low blood pressure happens because the chemicals released by extra mast cells, like histamine, cause blood vessels to widen and relax.
—Sarah Jividen, Verywell Health, 15 July 2024
Seasonal allergies are the body’s response to pollen from trees and grass; the immune system releases chemicals, like histamines, leukotrienes, and prostaglandins, which cause all those uncomfortable, familiar symptoms.
—Allie Volpe, Vox, 7 Dec. 2018
See All Example Sentences for histamine
Cite this Entry
“Histamine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/histamine. Accessed 22 Apr. 2025.
Copy CitationKids Definition
histamine
noun
his·ta·mine
ˈhis-tə-ˌmēn
-mən
: 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
histamine
noun
his·ta·mine
ˈhis-tə-ˌmēn
-mən
-mən
: 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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