Side effect

An unwanted effect thought to be caused by the treatment itself.

Learning 

What it means

A side effect is an unintended effect attributed to the treatment. It is narrower than an adverse event, which covers anything that happens regardless of cause.

Why it matters if you take part

Consent materials list known side effects from earlier studies. In early-phase studies the list is necessarily incomplete, because less is known.

Related terms

This explains how clinical research works. It is not medical advice and does not describe any specific condition or treatment. Only a trial site can determine whether someone can take part in a study.