Complex sentence: Glycyrrhizin can cause potassium levels in the body to fall, which causes some people to experience abnormal heart rhythms, as well as high blood pressure, edema (swelling), lethargy, and congestive heart failure.
Split into simpler sentences: Glycyrrhizin can cause potassium levels in the body to fall. When that happens, some people experience abnormal heart rhythms, as well as high blood pressure, edema (swelling), lethargy, and congestive heart failure.