Health researchers working in low-resource settings often encounter serious unmet health needs among participants. What is the nature and extent of researchers' obligations to respond to such needs? Competing accounts have been proposed, but there is no independent standard by which to assess them or to guide future inquiry. I propose an independent standard and demonstrate its use. In conclusion I recommend two areas of focus for future inquiry: what makes an account of researchers' obligations reasonable from the standpoint of both participants and researchers and how general duties of rescue apply to researchers' resource-allocation decision making in low-resource settings.