Corbett 1979.

Methods	Randomised controlled trial. Randomisation method not stated. Patient blinded. Unclear blinding of surgeon and outcome assessor.
Participants	105 patients enrolled in the study. Age‐range 5‐70.
Interventions	Treatment group: Metronidazole 1 g supp preoperatively and eight‐hourly for 3 days. (children <14: ½ dosis) Placebo group: supp regime as above.
Outcomes	Wound infection (Definite cellulitis and pyrexia, copious seropurulent discharge)
Notes	Some patients received drain.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear