side effect
noun
: a secondary and usually adverse effect (as of a drug)
toxic side effects
called also side reaction
Examples of side effect in a Sentence
Nausea and diarrhea are the side effects of the drug.
the harmful side effects of using chemicals to kill insects
The merger created positive side effects for both companies.
Recent Examples on the Web
Phase 4 tracks the potential benefits and side effects of a new treatment long-term after its approval.
—
Simon Spichak, Health, 11 July 2025
This is a reaction to rapid weight loss rather than a direct side effect of the medication.
—Jessica Swirble, Verywell Health, 10 July 2025
Apart from a risk of anemia, patients reported fewer side effects than standard pancreatic cancer medications.
—Amy Feldman, Forbes.com, 9 July 2025
Her battle was certainly not over because the radiation side effects were so intense.
—Alyce Collins, MSNBC Newsweek, 6 July 2025
See All Example Sentences for side effect
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.
Simon Spichak, Health, 11 July 2025
This is a reaction to rapid weight loss rather than a direct side effect of the medication.
—Jessica Swirble, Verywell Health, 10 July 2025
Apart from a risk of anemia, patients reported fewer side effects than standard pancreatic cancer medications.
—Amy Feldman, Forbes.com, 9 July 2025
Her battle was certainly not over because the radiation side effects were so intense.
—Alyce Collins, MSNBC Newsweek, 6 July 2025
See All Example Sentences for side effect
Cite this Entry
“Side effect.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/side%20effect. Accessed 23 Jul. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share