Although researchers generally take great care to ensure that human subjects do not suffer very serious harms from their involvement in research, the situation is different for nonhuman animal subjects. Significant progress has been made in reducing unnecessary animal suffering in research, yet researchers still inflict severe pain and distress on tens of thousands of animals every year for scientific purposes. Some bioethicists, scientists, and animal welfare advocates argue for placing an upper limit on the suffering researchers may impose on animal subjects, with rare exceptions for research that promises critical social benefits. In this article, I argue against such an upper limit on harm on the grounds that researchers often can compensate animal subjects for their suffering, even severe and long-lasting suffering. If animal subjects receive adequate compensation for the harms they suffer, then there is no general limit on how much suffering researchers may impose on them for scientific purposes.