All pharmacists' interventions were collected over a two-week period and were assessed for type and impact on patient care and medication costs. A total of 361 interventions were collected with a physician acceptance rate of 95.8 percent. Eighty-two of the 361 interventions were reviewed by seven physicians with 93 percent of those being judged to have had a positive effect on patient outcome, 7 percent were judged to have had no effect, while none reviewed were judged to be detrimental. Life-saving interventions were judged to have occurred in 8.5 percent of interventions, while 90 percent of the interventions were perceived to have resulted in improved quality of care and/or physician education. Cost analysis was performed comparing the difference of total medication costs (drug, pharmacy, nursing and drug assay costs) for a 24 hour period prior to and after the intervention occurred. The cost-avoidance over the two week period was calculated to be $679, representing a conservative estimate of an annual cost-avoidance of $17,654. Costs not evaluated were those avoided due to increased quality of care, decreased adverse drug effects and decreased length of hospital stay. Pharmacists' interventions which represent only a portion of a pharmacist's responsibilities, improve the quality of patient care and result in cost avoidance.