Safety and efficacy of a novel fecal microbiota transplantation method using hydrogen nanobubble water without antibiotics or bowel cleansing in children with autism spectrum disorder: an open-label, single-arm study demonstrating improvements in core and comorbidity symptoms.
Shirotani M, Shimizu S, Kitamura K, Mikawa Y, Haruna R, Kawai Y, Koide S, Mohri I, Matsuzaki H, Tsuchiya KJ, Tanaka Y, Katayama T. · Frontiers in Pediatrics. 2026;14:1767346.
What kind of evidence is this?
Human
Prospective open-label single-arm study
Other neurological conditions
Other forms
Positive for the combined procedure; indeterminate for molecular hydrogen.
Clinical symptom scales and microbiome outcomes for a combined intervention.
Methods at a glance
Children with autism spectrum disorder receiving fecal microbiota transplantation.
30 children enrolled in the single study arm.
30-week study period.
Fecal microbiota transplantation prepared with hydrogen nanobubble water, without antibiotic pretreatment or bowel cleansing.
Hydrogen nanobubble water used as the FMT preparation vehicle; not Brown's gas.
Approximately 100 g donor stool was mixed with 250 g hydrogen nanobubble water; a separately quantified administered H2 dose was not reported.
Not applicable — FMT preparation.
No oxygen was co-delivered.
No concurrent control and no FMT-without-hydrogen comparator.
Outcomes and reported result
Autism-related symptom scales, comorbidity measures, adverse events and microbiome measures.
Several symptom scores improved over time and the article reports no serious safety signal attributed to the procedure.
The full article, registration, protocol, results and adverse-event reporting were checked.
A reported association, difference or mechanism is not automatically a clinical benefit. Null findings, outcome type, study design and precision all matter.
Cautions and applicability
Open-label, uncontrolled and inseparable from FMT. Changes cannot be attributed specifically to hydrogen nanobubble water.
The combined FMT procedure studied; not hydrogen as a standalone intervention.
ROBINS-I — preliminary
Serious concerns
Critical confounding and expectation/time effects, with no control capable of isolating hydrogen.
Non-random selection or allocation · Confounding and co-intervention concerns · Attrition/reporting checked where stated · Some outcomes are subjective or laboratory-only · No outcome-level protocol comparison completed
No single-study GRADE certainty rating is assigned. Certainty is assessed by important outcome across a complete eligible evidence set, not by attaching a final grade to one source.
Sources and record status
PMID: 41890300 · DOI: 10.3389/fped.2026.1767346
Free full article in PubMed Central.
PubMed record and PubMed Central full text; extraction checked 9 August 2026.
2026-08-10