Thymus serpyllum Extract Improves Gastrointestinal Symptoms and Modulates Fecal Gut Microbiome Composition in a Multicenter, Randomized, Placebo-Controlled Clinical Trial
In brief
Wild thyme extract reduced gastrointestinal symptoms over 8 weeks in a randomized trial
In a placebo-controlled trial, adults taking wild thyme extract reported a greater reduction in gastrointestinal symptom burden and improved quality of life after 8 weeks; week-8 data were available for 131 of 178 participants. Overall microbiome diversity did not differ between groups, and the significance of specific microbial shifts remains unclear.
- Journal
- Medical sciences (Basel, Switzerland) (Q1)
- Published
- 28 September 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Raquel López-Zambrano, Jorge García-García, Laura López-Escánez, Teresa Vezza, Luckman Gbati, Rafael Palacios-López, et al.
- PMID
- 42930530
- DOI
- 10.3390/medsci14060611
Why clinicians should know about it
- Picked for Gastroenterology (top studies of the week, 1 November 2026): Thymus serpyllum reduced overall gastrointestinal symptom burden versus placebo
Abstract
BACKGROUND/OBJECTIVES: Functional gastrointestinal discomfort is highly prevalent and affects up to 40% of the global population and remains challenging to manage due to its multifactorial nature. Usual interventions include dietary and lifestyle modifications, such as targeted phytochemical-based interventions. This multicenter, double-blind, randomized, placebo-controlled trial investigated the efficacy and exploratory microbiome-related effects of a standardized wild thyme extract (WThE) administered for 8 weeks on gastrointestinal symptoms, health-related quality of life, and fecal microbiome dynamics in adults without diagnosed organic gastrointestinal disease who reported gastrointestinal discomfort. METHODS: A total of 178 adults without diagnosed organic gastrointestinal disease and with persistent gastrointestinal discomfort were randomized to WThE (n = 90) or placebo (n = 88); 131 participants had observed week-8 outcome data. RESULTS: The analysis showed a greater reduction in overall gastrointestinal symptom burden with WThE than placebo, measured by the GSRS total score, with the largest exploratory domain-level differences observed in indigestion, constipation, and diarrhea-related symptoms. Improvements were also observed in health-related quality of life. At the microbiome level, no significant between-group differences were detected in α- or β-diversity; however, taxon-level analyses identified specific changes in fecal microbial composition, and predicted functional profiling suggested associated pathway-level differences. Moreover, the extract was well tolerated, with no product-related adverse events reported during the 8-week intervention. CONCLUSIONS: Overall, WThE reduced self-reported gastrointestinal symptom burden and improved selected quality-of-life outcomes in adults with persistent gastrointestinal discomfort, supporting Thymus serpyllum as a safe and well-tolerated botanical intervention linked to favorable modulation of the fecal microbiome and enhanced gastrointestinal function. CLINICALTRIALS: gov no: NCT06639126.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.