The efficacy and safety of quetiapine fumurate in the treatment of patients with schizophrenia were evaluated in an 8-week, multicenter, open-label study. The results of this study which included a total of 54 patients showed good efficacy and safety profile for quetiapine fumarate as seen by the improvement rate (moderate or above in the final global improvement rating) of 49.1% and safety rate (no problem in overall safety rating) of 66.0%. The mean BPRS total score decreased significantly from 55.5 +/- 10.9 points at baseline to 45.4 +/- 13.0 points at the completion of administration. The PANSS scores also showed significant improvement on all scales; the mean scores decreased from 20.7 +/- 6.3 points at baseline to 17.7 +/- 6.9 points at withdrawal or completion of administration on the positive scale, from 27.8 +/- 5.8 points to 24.0 +/- 7.3 points on the negative scale, and from 51.4 +/- 10.1 points to 44.7 +/- 12.4 points on the general psychopathology scale. Although the most frequent adverse reactions were somnolence (18.9%), insomnia (17.0%), nervousness (13.2%), dizziness (13.2%), malaise (13.2%), postural hypotension (11.3%), tachycardia (9.4%), and constipation (9.4%), the incidence of extrapyramidal symptoms was low (11.3%). From these results, quetiapine fumarate was suggested to be highly effective and safe for the treatment of schizophrenia.