Dictionary
side' effect"
1. any effect of a drug, chemical, or other medicine that is in addition to its intended effect, esp. an effect that is harmful or unpleasant.
2. any accompanying or consequential and usually detrimental effect:
the side effects of air pollution. Also,side'-ef•fect".Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.