This case study involves the role of the kidneys in regulating blood pH and electrolytes. The case was used near the end of a two-semester Human Anatomy and Physiology course sequence, during the time when renal physiology was under study. Groups of two to three students were given the case and associated information (lab values, etc.). Students were allowed access to internet resources for any additional information they might need. Fifteen to 20 minutes were allowed for students to read the case and answer the associated questions, followed by a whole-class discussion. The case provides a starting point for health care discussions by introducing some basic principles of pharmacotherapy.