In this issue of JAMA Surgery, Newton et al1 present findings from a retrospective analysis of MarketScan Commercial Database health insurance claims data that documents that fluoroquinolone use vs comparator antibiotics is associated with an increased incidence of aortic aneurysm (AA) formation within 90 days in a large cohort of US adults. Mechanistically, this association is primarily for abdominal aortic and iliac artery aneurysms, not aortic dissections (ADs) or thoracic aortic aneurysms. The association was present across all age groups (≥35 to <65 years) and was consistent across sex and comorbidities. The study also documents that adult patients were more likely to undergo aneurysm repair (hazard ratio, 1.88; 95% CI, 1.44-2.46).