Adverse effects can occur when using medication, undergoing medical treatments, or even in common everyday situations. Instead of constantly using the phrase "adverse effect," there are several synonyms that can be used to vary your language. Some examples include: negative impact, adverse reaction, detrimental consequences, undesirable outcome, harmful effects, undesirable effects, and unfavorable consequences. By using synonyms, you can convey the same message with a different tone or emphasis. It can also help to avoid repetition and add some variety to your vocabulary. Most importantly, using synonyms for "adverse effect" can help you to communicate your thoughts more precisely and clearer to your audience.