The present research investigated how scientific authority increases the lethal use of animals in biomedical experimentation. In two behavioral studies (N = 151 and 150), participants were required to incrementally administer 12 doses of a toxic chemical to a 53-cm fish (in reality, a biomimetic robot) for research on animal learning. Consistent with the Engaged Followership Theory on obedience, participants placed in a pro-scientific mindset more severely harmed the laboratory animal. In a cross-sectional study (N = 351), participants in medical fields endorsed a more pro-scientific attitude than those in paramedical fields, which mediated their support for animal experimentation. Drawing on a representative European sample (N = 31,238), we also confirmed the specificity of this link by controlling for potential demographic and ideological confounds. In a final study (N = 1,598), instrumental harm was shown as mediating the link between a pro-scientific attitude and support for animal experimentation.