With health care reform came the advent of cost-conscious prescribing. Many measures contributed to this, including formulary control, physician education, and clinical pharmacy. Initial efforts in this regard were limited to the in-patient setting, but as health care reform continued, the significance of cost-effective prescribing in the ambulatory care setting has evolved. This article provides a brief historical look at cost-effective prescribing and how the efforts of a clinical pharmacist have successfully influenced the prescribing patterns for the acid-gastric products, and reduced expenditures in a Northern California health maintenance organization (HMO) medical center.