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 Among the myriad side effects of the pandemic: a surge in billboards and bus ads for personal injury law firms. Caroline Petrow-Cohen, Los Angeles Times, 24 Apr. 2024 However, those side effects are typically associated with higher doses of 45 milligrams per day or more. Sarah Anzlovar, Ms, Verywell Health, 23 Apr. 2024 That guessing game isn’t great when too much melatonin can lead to fatigue, dizziness, and confusion, among other wack side effects. Ali Finney, SELF, 19 Apr. 2024 Some parents and pediatricians worry about starting a teenager on buprenorphine, which can produce side effects including long-term dependence. Martha Bebinger, USA TODAY, 17 Apr. 2024 Minoxidil: Initially developed as an oral medication for severe hypertension in the 1970s, Minoxidil's unintended side effect of hair regrowth led to its topical application for treating alopecia in both men and women. Allison Futterman, Discover Magazine, 16 Apr. 2024 Adderall alternatives are typically natural substances that may improve executive function without the side effects of Adderall. Sponsored Content, The Mercury News, 12 Apr. 2024 Sadly, that’s not all the side effects she’s been dealing with. Sara Vallone, Miami Herald, 11 Apr. 2024 But these ingredients come with a range of side effects, with the most notable being a hangover effect the next day. Carly Weeks, TIME, 10 Apr. 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 28 Apr. 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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