Comparison 1. Systemic Antibiotics vs Placebo (Clinical).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Wound infection	47	8812	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.33 [0.29, 0.38]
1.1 Appendicitis	21	2343	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.31 [0.24, 0.42]
1.2 Simple appendicitis	26	5317	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.37 [0.30, 0.46]
1.3 Complicated appendicitis	24	1152	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.28 [0.21, 0.38]
2 Postoperative intra abdominal abscess	16	4468	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.43 [0.25, 0.73]
2.1 Appendicitis	8	1033	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.35 [0.13, 0.91]
2.2 Simple appendicitis	8	2968	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.46 [0.23, 0.94]
2.3 Complicated appendicitis	4	467	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.54 [0.12, 2.43]
3 Length of stay in hospital	8	1200	Mean Difference (IV, Fixed, 95% CI)	‐1.69 [‐1.78, ‐1.61]