Kim · Nutrients 2020 · pilot randomized controlled trial · n=24

The Effect of Ursodeoxycholic Acid on Small Intestinal Bacterial Overgrowth in Patients with Functional Dyspepsia: A Pilot Randomized Controlled Trial.

Cited 22 times in the scientific literature.

Level 2 - randomized trial

Individual randomized controlled trial.

PubMed 32422942 · doi:10.3390/nu12051410 · record verified 2026-08-29

What was done

Twenty-four patients diagnosed with functional dyspepsia (FD) and small intestinal bacterial overgrowth (SIBO) via lactulose breath test (LBT) were randomly assigned to either oral ursodeoxycholic acid (UDCA; 100 mg three times daily) or an untreated control group monitored for two months. Outcomes were evaluated after two months using the Nepean Dyspepsia Index-K for symptoms and repeat LBT for gas levels.

What was found

Dyspeptic symptoms significantly decreased from baseline in the UDCA-treated group and differed significantly from the untreated group at two months. In addition, total methane gas levels over 90 minutes during the LBT were significantly reduced from baseline in the UDCA group. The abstract did not report exact numerical scores, gas measurements, variance, or p-values.

Why it matters

This study provides preliminary evidence that UDCA may reduce methane-producing bacterial overgrowth and relieve dyspeptic symptoms in patients with functional dyspepsia.

Limits

The sample size was very small (n = 24). The control arm was untreated rather than placebo-controlled, introducing high risk of bias for subjective symptom reporting. The abstract reports no numerical values, hydrogen gas outcomes are not described, and long-term durability is unknown.

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