A randomized double-blind prospective study on the efficacy of single-dose antibiotic prophylaxis compared cefuroxime versus metronidazole versus the combination of both agents in vaginal hysterectomy. Overall antibiotic prophylaxis was effective in abscess prevention (one abscess in 68 patients). In the metronidazole group a significantly higher grade of morbidity was observed: febrile morbidity 41% versus 4% in the two other groups; bacteriuria 73% versus 17% in the cefuroxime group, versus 13% in the combined group; urinary tract infection 23%, versus 0% in the two other groups; post-operative prescription of antibiotics 41%, versus 0% in the two other groups. Febrile morbidity and bacteriuria correlated positively with Escherichia coli and Proteus spp. These micro-organisms were recovered significantly more often from the vagina of patients in the metronidazole group. Cefuroxime was successful, metronidazole failed in the prevention of minor morbidity. We could not observe any effect from the addition of metronidazole to the cefuroxime prophylaxis.