A randomized double-blind placebo-controlled trial of rifaximin in patients with abdominal bloating and flatulence

Am J Gastroenterol. 2006 Feb;101(2):326-33. doi: 10.1111/j.1572-0241.2006.00458.x.


Aims: To study the efficacy of rifaximin, a nonabsorbable antibiotic, in relieving chronic functional symptoms of bloating and flatulence.

Methods: Randomized double-blind placebo-controlled trial consisting of three 10-day phases: baseline (phase 1), treatment with rifaximin 400 mg b.i.d. or placebo (phase 2), and post-treatment period (phase 3). Primary efficacy variable was subjective global symptom relief at the end of each phase. A symptom score was calculated from a symptom diary. Lactulose H2-breath test (LHBT) was performed at baseline and end of study.

Results: One hundred and twenty-four patients were enrolled (63 rifaximin and 61 placebo). Baseline characteristics were comparable and none had an abnormal baseline LHBT. Rome II criteria were met in 58.7% and 54.1%, respectively. At the end of phase 2, there was a significant difference in global symptom relief with rifaximin versus placebo (41.3% vs 22.9%, p = 0.03). This improvement was maintained at the end of phase 3 (28.6% vs 11.5%, p = 0.02). Mean cumulative and bloating-specific scores dropped significantly in the rifaximin group (p < 0.05). Among patients with IBS, a favorable response to rifaximin was noted (40.5% vs 18.2%; p = 0.04) persisting by the end of phase 3 (27% vs 9.1%; p = 0.05). H2-breath excretion dropped significantly among rifaximin responders and correlated with improvement in bloating and overall symptom scores (p = 0.01). No adverse events were reported.

Conclusions: Rifaximin is a safe and effective treatment for abdominal bloating and flatulence, including in IBS patients. Symptom improvement correlates with reduction in H2-breath excretion. Future trials are needed to examine the efficacy of long-term or cyclic rifaximin in functional colonic disorders.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Breath Tests
  • Double-Blind Method
  • Female
  • Flatulence / diagnosis
  • Flatulence / drug therapy*
  • Follow-Up Studies
  • Gastrointestinal Agents / therapeutic use*
  • Humans
  • Hydrogen / analysis
  • Lactulose
  • Male
  • Rifamycins / therapeutic use*
  • Rifaximin
  • Treatment Outcome


  • Gastrointestinal Agents
  • Rifamycins
  • Lactulose
  • Hydrogen
  • Rifaximin