Biologics can have a range of side effects, including fatigue, reactions at the injection site, and a scaly skin rash, called psoriasis.

Because biologics affect the immune system, in rare cases they can cause more serious side effects, such as infections. Also, the biologics that work by blocking TNF may lead to lymphoma—a form of blood cancer.

However, the risk of getting lymphoma or a serious infection is very low. The next two pages will help you better understand these risks.