alkaloid
noun
al·ka·loid
ˈal-kə-ˌlȯid 
: any of numerous usually colorless, complex, and bitter organic bases (such as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active
Examples of alkaloid in a Sentence
Recent Examples on the Web
Too many alkaloids, though, can make the plant toxic to humans.
—
New Atlas, 29 June 2025
Despite possessing toxic skin alkaloids, poison frogs (Family: Dendrobatidae) have long been favorites because of their bright colors and patterns and their complex parental care behaviors.
—Grrlscientist, Forbes.com, 18 May 2025
The alkaloid, called atropine, is administered to increase heart rate, reduce saliva and fluid in the respiratory tract during surgery, and treat insecticide or mushroom poisoning.
—Nina Foster, JSTOR Daily, 30 May 2025
But the alkaloids in tea allow the body to absorb the caffeine much more slowly, lessening the chance of experiencing that annoying coffee crash.
—Christina Pérez, Vogue, 27 May 2025
See All Example Sentences for alkaloid
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New Atlas, 29 June 2025
Despite possessing toxic skin alkaloids, poison frogs (Family: Dendrobatidae) have long been favorites because of their bright colors and patterns and their complex parental care behaviors.
—Grrlscientist, Forbes.com, 18 May 2025
The alkaloid, called atropine, is administered to increase heart rate, reduce saliva and fluid in the respiratory tract during surgery, and treat insecticide or mushroom poisoning.
—Nina Foster, JSTOR Daily, 30 May 2025
But the alkaloids in tea allow the body to absorb the caffeine much more slowly, lessening the chance of experiencing that annoying coffee crash.
—Christina Pérez, Vogue, 27 May 2025
See All Example Sentences for alkaloid
Cite this Entry
“Alkaloid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/alkaloid. Accessed 8 Jul. 2025.
Copy CitationMedical Definition
alkaloid
noun
al·ka·loid
ˈal-kə-ˌlȯid
: any of numerous usually colorless, complex, and bitter organic bases (as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active
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