Children in whom non-operative treatment is successful will receive a minimum of 12 hours intravenous antibiotics and then be switched to oral antibiotics once they have shown clinical improvement. They will be discharged home once they meet a standardized set of criteria to be used in all centers: vital signs (including temperature) within normal limits, tolerating a light diet orally, adequate oral pain relief and mobile. They will receive a total course of 10 days of antibiotics (intravenous and oral) following randomization.