Acute pelvic inflammatory disease is a serious medical and economic consequence of sexually transmitted diseases among young women. The aim of the study is to compare the efficacy and safety of gentamycin plus clindamycin with that of ceftazidime plus doxycycline in the treatment of hospitalized patients with acute pelvic inflammatory disease. A total of 78 patients with acute PID, hospitalized in II Obstretic and Gynecologic Clinic of II University of Naples (Italy), entered and randomized into two treatment groups: gentamycin plus clindamycin (N = 40) and ceftazidime plus doxycycline (N = 36). Patients were excluded if they were pregnant or were not over the age of 16 years of had a history of allergy to one of the drugs used in the Study of had hepatic disease or kidney trouble or had IUD. Acute PID was diagnosed by the following criteria: 1) lower abdominal pain; 2) cervical motion tenderness; 3) adnexal tenderness (all three should be present); plus at least one of the following additional criteria: a) temperature over 38 degrees C; b) leukocytosis (greater than 10.500 mm3); c) purulent material from the peritoneal cavity bt culdocentesis; d) inflammatory mass present on binomial pelvic examination and/or sonography; e) erythrocyte sedimentation rate > 15 mm/hr. Patients were enrolled into the study after obtaining informed consent, pretreatment and posttreatment cultures were obtained from the endocervix from Neisseria gonorrhoeae and Chlamydia trachomatis and aerobic-anaerobic bacteria. The study has shown that the acute PID has a polymicrobal origins. Both antibiotic regimens were very effective in the treatment of the PID: a complete recovery was obtained in over 90% of patients.