What the heck is chemo brain?? Sharon and Lucy are here to answer that question! If you or someone in your life is facing chemotherapy, you will want to know about this topic. This little chemo side-effect can be a bit alarming if you are not prepared, but it is not at all unusual. As a matter of fact, the forgetfulness (and that is an understatement) that can accompany chemo therapy has made for some funny stories.