This article examines the role of stigma in social and institutional responses to infectious disease emergencies, to better understand and minimize these dynamics in the event of a pandemic of virulent influenza. In addition to their impact on human suffering, fear and stigma can seriously delay detection and treatment efforts, cooperation with contact tracing and isolation measures, and the effective distribution of resources for the prevention and control of infectious diseases. These dynamics are illustrated by the Indian plague epidemic of 1994, which occurred in a region where H5N1 influenza has been detected recently. Public fear and stigma also played a significant role in the social and institutional responses to the 1918 influenza pandemic. These historical models provide important lessons for pandemic preparedness and global health policy.