Why does immunotherapy cause side effects?

Immunotherapy can cause side effects, and they happen for a specific reason. According to the National Cancer Institute, immunotherapy can cause side effects, many of which happen when the immune system that has been revved up to act against the cancer also acts against healthy cells and tissues in your body.

In other words, the same boosted immune response that helps fight cancer can sometimes affect normal, healthy parts of the body too.

The National Cancer Institute has more detailed information on immunotherapy side effects. Your healthcare team can tell you which side effects to watch for with your specific treatment, and when you should call them.