As Coser (1962) demonstrated in her landmark hospital study, a humor is one of the great tools of reassurance on the hospital ward. After all, if something is ridiculous, how can it be threatening? In this study, the authors examine the role of humor in medical interactions, with an eye toward greater understanding of the means by which people manage the emotions of others. Through face to face interviews with 22 providers in a large hospital, this study garners empirical support for a previously developed definition of humor as interpersonal emotion management. In addition, the study uncovers the particular roles played by the contextual factors of humor, including actor, setting, and timing. These factors are critical in determining whether humor is appropriate and successful in achieving desired emotional change, or whether it will fail or even backfire, causing emotional and interactional harm. The study draws implications for the potential study of harmful coping and social support.