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
For example, certain diuretics, antihistamines or stimulants may increase the risk of side effects from heat, according to the CDC.
—
Dinah Voyles Pulver,
USA Today,
3 July 2026
Taking more than your body needs can actually cause vitamin toxicity, leading to side effects that range from mild discomfort to serious health problems.
—
Anna Giorgi,
Verywell Health,
3 July 2026
That kind of determination may involve job duties, transportation, treatment side effects, fluctuating symptoms and the difference between working sometimes and working consistently.
—
Michelle Mbekeani,
Forbes.com,
1 July 2026
One of the lasting side effects of the COVID-19 pandemic and our catastrophically incompetent response to it is the decrease in trust in public health experts and their advice.
—
Ian Miller Outkick,
FOXNews.com,
1 July 2026
See All Example Sentences for side effect
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Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
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Dinah Voyles Pulver,
USA Today,
3 July 2026
Taking more than your body needs can actually cause vitamin toxicity, leading to side effects that range from mild discomfort to serious health problems.
—
Anna Giorgi,
Verywell Health,
3 July 2026
That kind of determination may involve job duties, transportation, treatment side effects, fluctuating symptoms and the difference between working sometimes and working consistently.
—
Michelle Mbekeani,
Forbes.com,
1 July 2026
One of the lasting side effects of the COVID-19 pandemic and our catastrophically incompetent response to it is the decrease in trust in public health experts and their advice.
—
Ian Miller Outkick,
FOXNews.com,
1 July 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 5 Jul. 2026.
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