An investigator planning a study in Africa of the prevalence of pulmonary hypertension in children with severe malaria anticipates that she and her team will encounter significant unmet health needs during the course of the study. She recognizes that study procedures, particularly echocardiography, may identify and diagnose conditions that are not treatable within the local health system due to resource constraints. Aware that some of these needs may be serious, as well as difficult and costly to treat, she asks the bioethics consultation service for assistance in determining the extent to which she as an investigator has a responsibility to provide clinical care for conditions that she finds while conducting the study. This article reviews the issue of investigators' responsibilities to meet participants' needs for ancillary care and argues that investigators can have a responsibility to provide care for a wide range of health needs, including at times care for conditions not connected to the research question or study procedures. That responsibility, however, is significantly limited by the depth of the investigator's relationship with participants and the resource demands of providing such care.