The effect of a psychopharmacy consultation service on outcomes in patients with psychiatric disorders was studied. The medical records of 30 randomly selected patients who had been hospitalized between August 1990 and July 1992 at a private psychiatric institution and who had been seen by the psychopharmacy consultation service during that period were reviewed. Data obtained included (1) patient demographics, (2) patient information generated by the psychopharmacy consultation, (3) the types of recommendations made by the psychopharmacy specialist and whether the recommendations were accepted by the physician, and (4) the clinical outcome. Forty-three psychopharmacy consultations for the 30 patients were evaluated. A total of 125 recommendations were made by the consultation service; of these, 75 (60%) were accepted. The consultations were divided into consultations for which at least a majority of the resulting recommendations were accepted by the physician (n = 29) and consultations for which less than a majority of the recommendations were accepted (n = 14). For the majority group, 23 (79%) of the 29 consultations were associated with a positive outcome, compared with 2 (14%) of the 14 consultations in the less-than-majority group. Similarly, positive outcomes were significantly more frequent in the majority-group patients (16/21 [76%]) than in the less-than-majority-group patients (2/9 [22%]). The frequency of positive outcomes was higher among patients for whom most of the recommendations of a clinical psychopharmacy consultation service were accepted than among patients for whom most recommendations were not accepted.