The choice of antibiotics will vary between center and will be the antibiotic regimen that is current standard of care in that center. This is due to (i) varying antibiotic regimes among participating centers at present influenced by local factors, including antimicrobial stewardship and drug cost (26) and (ii) a lack of evidence to support a specific antibiotic regimen for childhood appendicitis. Allowing each center to maintain current antibiotic protocols will improve study feasibility and increase generalizability of the results. However, the duration of combined intravenous and oral therapy will be standardized to 10 days.