Comparison 6. Per‐operatively administered single agent, single dose Antibiotics vs Placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Wound infection	12	3358	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.43 [0.34, 0.55]
1.1 Appendicitis	6	585	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.37 [0.22, 0.60]
1.2 Simple appendicitis	6	2347	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.52 [0.37, 0.73]
1.3 Complicated appendicitis	5	426	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.35 [0.21, 0.58]
2 Postoperative intra abdominal abscess	3	2115	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.67 [0.32, 1.42]
2.1 Appendicitis	2	380	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.69 [0.12, 3.99]
2.2 Simple appendicitis	1	1554	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.74 [0.31, 1.79]
2.3 Complicated appendicitis	1	181	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.32 [0.03, 3.29]
3 Length of stay in hospital	2	209	Mean Difference (IV, Fixed, 95% CI)	‐0.80 [‐1.34, ‐0.26]