Most published biomedical research involving animal models is evaluated carefully to ensure that appropriate ethical standards are met. In the current study, 500 journals randomly selected from MedLine were assessed for whether they presented animal research. Of the 138 journals that did, the instructions to authors of 85 (61.6%) included a requirement for author assurance of adherence to ethical standards during experiments involving animals. In comparison to a wider range of biologic journals, biomedical science journals were more likely to have some sort of ethical policy concerning the reporting and presentation of animal experiments.