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 In its paper, Cognito highlighted that its treatment did not cause these adverse events or other serious side effects. Emily Mullin, WIRED, 6 Mar. 2024 The review of ketamine clinics' claims in ads on Google found the businesses rarely disclosed potential side effects, while aggressively marketing its benefits. Darius Tahir, CBS News, 5 Mar. 2024 After testing revealed his tumor in 2013, Alvarez became determined to fast-track his creative career while postponing any surgical procedure for fear of debilitating side effects, like problems speaking or walking. Miles Klee, Rolling Stone, 5 Mar. 2024 Potential side effects include headaches, bloating and cramping. Sydney Lupkin, NPR, 4 Mar. 2024 The drugs have shown effectiveness in helping with obesity, diabetes and even heart problems (though some patients have also reported side effects including nausea, diarrhea and heart palpitations). Jennifer Hassan, Washington Post, 29 Feb. 2024 Other possible side effects, according to the waiver and release of liability form, include: Pain Sickness Short-term or permanent ailment The franchise has locations in 15 states including California, New York, Florida, Alabama and Illinois. Brianna Taylor, Sacramento Bee, 27 Feb. 2024 Xolair comes with the risk of a few side effects, including joint pain, fever, and anaphylaxis. Korin Miller, Verywell Health, 22 Feb. 2024 Television Michael Strahan finally explains ‘GMA’ absence: His 19-year-old’s brain cancer battle Jan. 11, 2024 Documenting her first round of chemo, Isabella’s recent videos offered followers a look at her treatment and detailed its side effects, ranging from eye and jaw pain to headaches. Alexandra Del Rosario, Los Angeles Times, 21 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'side effect.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1814, in the meaning defined above

Time Traveler
The first known use of side effect was in 1814

Dictionary Entries Near side effect

Cite this Entry

“Side effect.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/side%20effect. Accessed 19 Mar. 2024.

Kids Definition

side effect

noun
: an often harmful and unwanted effect (as of a drug) that occurs along with the basic desired effect
the environmental side effects of using chemicals to kill pests

Medical Definition

side effect

noun
: a secondary and usually adverse effect (as of a drug)
toxic side effects
a side effect of drowsiness caused by antihistamines

called also side reaction

Last Updated: - Updated example sentences
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