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

While carrageenan is generally safe to consume, there are some medical interactions and possible side effects. —Laura Schober, Health, 17 July 2024

Because there are few side effects and the promise of minimal scarring following Mohs surgery, many people opt for the procedure over other forms of care to cure their skin cancer. —Angelica Bottaro, Verywell Health, 17 July 2024

If someone is experiencing side effects that are uncomfortable or bothersome, Dr. Tarlow advises those individuals to speak with their doctor. —Sandra Rose Salathe, Flow Space, 17 July 2024

But what Gen Z is likely noticing are the potential side effects, which are temporary. —Charlie Carballo, WWD, 17 July 2024

Word History

First Known Use

1814, in the meaning defined above

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