side effect

Or side-ef·fect

noun

1. any effect of a drug, chemical, or other medicine that is in addition to its intended effect, especially an effect that is harmful or unpleasant.

2. any accompanying or consequential and usually detrimental effect.

   the side effects of air pollution.

side effect

noun

1. any unwanted nontherapeutic effect caused by a drug Compare aftereffect

2. any secondary effect, esp an undesirable one

Word History and Origins

Origin of side effect¹

First recorded in 1880–85

Example Sentences

"But if millions of healthy people start using them - some without medical need - we may begin to see rare side effects more regularly," he adds.

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Prasad, in the email, said the deaths finding was based on an “initial analysis” of case reports from an FDA safety system that collects information from the public and doctors about potential vaccine side effects.

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However, in cancer care these procedures typically require high doses of chemotherapy and radiation to eliminate the original blood and immune system, which often causes serious side effects.

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Many users stay away from greasy, creamy and sweet foods because they can exacerbate side effects such as nausea.

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At Amama's headquarters in the city of Seville, a mosaic promoting self-examinations and leaflets advertising flamenco classes to fight the side effects of chemotherapy welcome breast cancer sufferers.

Read more on Barron's

Related Words

• aftereffect 
• reaction