Am J Gastroenterol

Antibiotic exposure tied to higher odds of IBD flare-ups

January 21, 2026

This self-controlled case series of 810 adults with IBD in Hong Kong found that antibiotic use for non-GI infections was associated with short-term increases in flare incidence. Flare risk was elevated in the month before antibiotics (incidence rate ratio [IRR], 2.85), rose further during treatment (IRR, 3.44), and peaked within two weeks after therapy (IRR, 4.79), before returning to baseline by six months. Oral antibiotics were associated with increased flare risk during and shortly after treatment (IRRs, 3.91 and 3.70), whereas injectable agents weren't. Broad-spectrum antibiotics showed higher IRRs than narrow-spectrum agents across several risk windows.

Clinical takeaway: When treating non-GI infections in patients with IBD, consider route and spectrum, as oral and broad‑spectrum antibiotics were associated with higher short‑term flare risk.

Source:

Zhang Y, et al. (2026, January 3). Am J Gastroenterol. Association Between Antibiotic Use for Non-Gastrointestinal Infections and Inflammatory Bowel Diseases Flare-Ups: A Self-Controlled Case Series Study. https://pubmed.ncbi.nlm.nih.gov/41533458/