Clinical Research Glossary

side effect side effect


A health change that is not the intended effect of the treatment and usually considered a problem.

Example of side effect in a sentence

A side effect is not the main effect of the treatment.

More Info

Side effects are things that are known to be a possible effect of a treatment.

For example, a side effect of taking aspirin is excess bleeding. Often times, a side effect is unwanted, but in some cases a side effect could be considered a good thing.

Other info to think about when joining a study

Known side effects are listed in the consent form. A member of the study team may also tell you about possible side effects.

Ask any questions about the side effects and how likely they are. You can also ask what you should do if you think you are getting a side effect and who you should tell.

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