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
Enzymes in the frogs' bodies turn the alkaloids in ants, small beetles, millipedes and mites into toxins, Schwarcz wrote in an article first published in the Montreal Gazette.
—
Dinah Voyles Pulver, USA Today, 15 Feb. 2026
The bitter bunch contains high levels of toxic alkaloids and must be soaked for several days to ensure safe consumption.
—Randi Gollin, Martha Stewart, 15 Feb. 2026
While modern tomatoes have evolved to no longer produce the eggplant alkaloids, those on the western Galápagos Islands had seemingly re-evolved, or de-evolved, to contain this ancestral gene.
—Taylor Nicioli, CNN Money, 30 Oct. 2025
However, butterbur contains pyrrolizidine alkaloids, which are substances that can be toxic to the liver and potentially carcinogenic.
—Colleen Doherty, Verywell Health, 26 Oct. 2025
See All Example Sentences for alkaloid
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Dinah Voyles Pulver, USA Today, 15 Feb. 2026
The bitter bunch contains high levels of toxic alkaloids and must be soaked for several days to ensure safe consumption.
—Randi Gollin, Martha Stewart, 15 Feb. 2026
While modern tomatoes have evolved to no longer produce the eggplant alkaloids, those on the western Galápagos Islands had seemingly re-evolved, or de-evolved, to contain this ancestral gene.
—Taylor Nicioli, CNN Money, 30 Oct. 2025
However, butterbur contains pyrrolizidine alkaloids, which are substances that can be toxic to the liver and potentially carcinogenic.
—Colleen Doherty, Verywell Health, 26 Oct. 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 22 Feb. 2026.
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
Love words? Need even more definitions?
Merriam-Webster unabridged
