Participants undergoing standard of care (SOC) with simple appendicitis will not receive post-operative antibiotics.

Participants undergoing standard of care (SOC) with complicated (gangrenous or perforated) appendicitis will receive 24 hours of SOC post-operative antibiotics.

Use of Standard of Care Antibiotics, type as determined by the clinician, will be restricted to none or 24 hours of post-operatively.

Participants undergoing standard of care (SOC) with simple appendicitis will receive 24 hours of post-operative antibiotics.

Participants undergoing standard of care (SOC) with complicated (gangrenous or perforated) appendicitis will receive 4 days of SOC post-operative antibiotics.

Use of Standard of Care Antibiotics, type as determined by the clinician, will be permitted for 24 hours or 4 days of post-operatively.

Type of antibiotic is per clinical judgement with the duration being the experimental aspect of this study.

All subjects will be contacted at least 30 days after appendectomy by telephone if unable to contact subject, then electronic medical record will be reviewed. Outcomes will be assessed by Desirability of Outcome Ranking (DOOR), with the lowest ranking of 1 indicating no adverse effects. Infectious/antibiotic complications requiring antibiotic treatment only, Emergency Department visit, hospital readmission, percutaneous drainage, operative intervention, and death ranked 2 through 7. A lower score indicates a more desirable outcome. For subjects of same DOOR score, Response Adjusted for Duration of Antibiotic Risk (RADAR) scores will be used to determine the better outcome. The distribution of DOOR scores and associated statistical analyses will be reported.

All subjects will be monitored from consent until follow up at least 30 days after appendectomy for number of complications. Each event will be assessed by National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) v.5.0, with the lowest grade being 1 and the highest grade of 5 indicating death. A higher grade indicates a more serious event.