Objective. To determine whether pharmacy students' prior beliefs and attitudes about drug products and dietary supplements affected their ability to analyze the quality of research study abstracts and use them in making drug recommendations to patients. Methods. Fifty-nine Doctor of Pharmacy (PharmD) students in a drug literature course were randomly assigned to receive one of two forms to evaluate four drug literature abstracts of varying quality and study design. On each form, there were two abstracts that had been taken directly from published research studies and two abstracts in which a different product had been substituted for the actual product studied. Pharmacy students completed a questionnaire about the studies to determine whether their evaluation of quality was affected by their prior opinions about the products. Results. Students correctly recognized the relative quality of the studies. However, after reading abstracts of research articles that were identical except for the product named, students were still more likely to recommend drugs approved by the Food and Drug Administration than dietary supplements. Conclusion. Pharmacy students' evaluation of clinical research studies was mildly influenced by confirmation bias but more so by the quality of the research.