Kortelainen 1982.

Methods	Clinical controlled trial. Allocation based on the last digit of the patients birth year.
Participants	315 eligible patients, 278 enrolled. Age range 15‐83 years, 159 males and 119 females
Interventions	Treatment group: Metronidazole suppository (1 g) 30‐60 min preoperatively. Control group: No antimicrobial therapy
Outcomes	Wound infection, defined as the presence of pus or a purulent exudate at the wound
Notes	Appendicitis defined as either normal, inflamed or gangrenous
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	High risk	C ‐ Inadequate