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
According to the website of Wegovy, another popular brand, the most common side effects include nausea, diarrhea, vomiting, constipation, abdominal pain, and headaches.
—
Ayushi Shah, CNN Money, 8 Feb. 2026
Cagrilintide might also ease some of GLP-1 drugs’ common gastrointestinal side effects, such as severe nausea and vomiting, says Jesse Richards, an internal medicine and obesity clinician at the University of Oklahoma School of Community Medicine.
—Bethany Brookshire, Scientific American, 6 Feb. 2026
Some current obesity drugs have the side effect of losing muscle mass in addition to fat.
—Chris Hoffman, CBS News, 6 Feb. 2026
As early as 2017, a Pew Research study found that Black parents were less likely than white parents to see the health benefits of the MMR vaccine and more likely to consider the risks of potential side effects.
—Ej Dickson, Rolling Stone, 6 Feb. 2026
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.
Ayushi Shah, CNN Money, 8 Feb. 2026
Cagrilintide might also ease some of GLP-1 drugs’ common gastrointestinal side effects, such as severe nausea and vomiting, says Jesse Richards, an internal medicine and obesity clinician at the University of Oklahoma School of Community Medicine.
—Bethany Brookshire, Scientific American, 6 Feb. 2026
Some current obesity drugs have the side effect of losing muscle mass in addition to fat.
—Chris Hoffman, CBS News, 6 Feb. 2026
As early as 2017, a Pew Research study found that Black parents were less likely than white parents to see the health benefits of the MMR vaccine and more likely to consider the risks of potential side effects.
—Ej Dickson, Rolling Stone, 6 Feb. 2026
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 8 Feb. 2026.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
