Pelvic inflammatory diseases observed within 5 years in the department of obstetrics and gynaecology of the University of Szeged and caused by intrauterine conception have been studied retrospectively. The cases were 78 times mild and 53 times severe. Mostly the symptoms could be observed following long-time use. Treatment was a combination of chloramphenicol and gentamycine with addition of metronidazole. If there was no remission colpotomy and drainage were performed. If this manoever was not successfull laparotomy (salpingoophorectomy, hysterectomy) was necessary. Intraperitoneal lavage with antibiotics was done by means of a drain. The authors are of the opinion, that insertion of IUD is allowed only in cases of negative gynaecological findings. Continuous supervision is compulsory. In cases of minimal complaints removal of IUD has to be considered.