Forty-four patients with severe pelvic inflammatory disease were randomly divided into two groups. Single drug therapy with the amoxicillin-clavulanic acid was used in 22 patients (group A). The other 22 patients (group B) were given a combination of ampicillin, gentamicin and metronidazole. Clinical results were comparable in both groups with 91% successes and 9% improvements in group A, against 86% successes, 9% failures, and 5% non-interpretable results in group B. The difference between the two groups was not statistically significant (p = 11.6%). 30% of patients in each group had positive serologic tests for Chlamydiae. This had no influence on therapeutic results but led to secondary prescription of a cycline. Because amoxicillin-clavulanic acid is active against aerobic and anaerobic pathogens, including beta-lactamase-producing microorganisms, it is a satisfactory alternative to the ampicillin-gentamicin-metronidazole combination, especially as it is simpler to use, less toxic and less expensive.