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
Just know that, like most antibiotics, azithromycin can mess with your GI tract, potentially triggering side effects like diarrhea or nausea.
—
Erica Sloan, SELF, 13 Feb. 2025
However, there have been reports of people experiencing mild side effects, such as nausea, bloating, indigestion, and gas.23
People with fish allergies may experience allergic reactions to marine collagen, so carefully reading the supplement label is crucial to avoid consuming potential allergens.
—Devineé Lingo, M.s., Health, 12 Feb. 2025
Nutrients to provide the building blocks, and lower carbs to help stabilize your blood sugar and even out the roller coaster of spikes and drops that create so many cognition-impairing side effects, including lightheadedness, anxiety, fatigue, irritability and a decrease in focus.
—Heather Sandison, Contributor, CNBC, 11 Feb. 2025
This suggests the gray matter reductions detected are not related to sleep disruptions but perhaps a unique side effect of caffeine.
—New Atlas, 11 Feb. 2025
See all Example Sentences for side effect 
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Erica Sloan, SELF, 13 Feb. 2025
However, there have been reports of people experiencing mild side effects, such as nausea, bloating, indigestion, and gas.23
People with fish allergies may experience allergic reactions to marine collagen, so carefully reading the supplement label is crucial to avoid consuming potential allergens.
—Devineé Lingo, M.s., Health, 12 Feb. 2025
Nutrients to provide the building blocks, and lower carbs to help stabilize your blood sugar and even out the roller coaster of spikes and drops that create so many cognition-impairing side effects, including lightheadedness, anxiety, fatigue, irritability and a decrease in focus.
—Heather Sandison, Contributor, CNBC, 11 Feb. 2025
This suggests the gray matter reductions detected are not related to sleep disruptions but perhaps a unique side effect of caffeine.
—New Atlas, 11 Feb. 2025
See all Example Sentences for side effect
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 21 Feb. 2025.
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