Although much of the pedagogical literature suggests otherwise, not all students find case-based instruction interesting and valuable or are confident learning from this method. This exploratory study examined how students responded to case-based instruction by exploring similarities and differences among nine students' experiences in a case-based biochemistry course. Nine first-year veterinary students were interviewed three times during the semester to explore their initial and changing responses to case-based instruction. Patterns of responses which emerged during the analysis revolved around changing levels of motivational challenge, frustration, and perceived relevance and stimulation of the method. Implications for the development and use of case studies in professional education programs are discussed. (Contains 11 references.) (Author/SWC)