For medical students, we combine the laboratory practice with clinical applications by developing biochemical and molecular biology experiments. In this experiment, students first collect their own buccal epithelial cells by a noninvasive mouthwash method. Then, they extract genomic DNA and perform polymerase chain reaction (PCR) to amplify angiotensin-converting enzyme (ACE) gene using genomic DNA as a template. Finally, the polymorphism of ACE gene is observed by electrophoresis. Students not only learn the techniques but also acquire knowledge of the ACE gene polymorphism. By establishing the relationship among ACE polymorphism and high blood pressure and myocardial hypertrophy, students should be able to understand the gene polymorphism and its association with susceptibility to disease. This laboratory practice teaching can also stimulate desire to do scientific research. Experimental results from many individuals can help us determine and analyze the fractions of ACE gene types in Chinese cohorts. Such an experiment strongly activates students and provides a solid foundation for the medical students' future research and clinical application.