In accordance with the criteria for clinical evaluation, established by the UTI research group, 43 cases of chronic bacterial prostatitis were retrospectively analyzed. The subjective symptoms were "resolved" in 18.5%, "improved" in 46.5%, and "persisted" in 34.9%. The white blood cells were "cleared" in 34.9%, "decreased" in 37.2%, and "unchanged" in 27.9%. The bacteria were "eliminated" in 51.2%, "decreased" in 16.2%, "replaced" in 11.6%, and "unchanged" in 21.0%. Overall clinical efficacy was "excellent" in 51.2%, "moderate" in 39.5%, and "poor" in 27.9%, with an overall effectiveness rate of 72.1%. Bacteria (isolated bacteria: 8 species, 52 strains) were "eradicated" in 69.2% (GNR 71.4%, GPC 66.7%), and "persisted" in 30.8%. The bacterial eradication rate was 87.5% for E. coli, 58.3% for S. epidermidis, and 75.0% for E. faecalis. The analytical results of the clinical effects, classified by characteristic factor, showed significantly better results, in the excellence rate (p less than 0.05) and the overall effectiveness rate (p less than 0.01) of primary cases as compared with relapse cases. Among the isolated bacterial species, GNR showed more favorable results in comparison with GPC but without any significant difference. Further, the results of 81.3% for E. coli, 66.7% for S. epidermidis, and 62.5% for E. faecalis, indicates no significant difference between respective bacterial species. The new quinolones showed a favorable rate of 92%, followed by 80% of ST (sulfamethoxazole-trimethoprim), and 78% of tetracyclines, with a significant difference (p less than 0.01) in comparison with the mean overall effectiveness rates of cephems, penicillins, and old quinolones.(ABSTRACT TRUNCATED AT 250 WORDS)