Editor: Chun-Su Yuan, MD, PhD, is the Cyrus Tang Professor in the Department of Anesthesia & Critical Care at the Pritzker School of Medicine, University of Chicago. Since 1994, Dr.Yuan has been conducting clinical trials evaluating the safety and efficacy of a novel peripheral opioid receptor antagonist, methylnaltrexone, for reversing opioid-induced bowel dysfunction. He has published over 150 research papers, including many articles on opioid action and antagonism of opioid side effects.