Foster 1981 A.

Methods	Randomised controlled trial. Randomisation methode not stated. Doubleblinding. Unclear blinding of outcome assesor.
Participants	496 patients enrolled in the study. The study has 3 subgroups (see Foster 1981 B). In Foster 1981 A 377 patients enrolled in the study.
Interventions	Treatment group: Metronidasole 1 g supp 40 min preoperatively. Placebo group: Identical supp 40 min preoperatively.
Outcomes	Wound infection (not defined)
Notes	Some patients got drain treatment.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear