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
A single hydrogen-water enema packed with donor stool cut autism traits by almost one-third for a full year.
01Research in Context
What this study did
Doctors gave kids with autism a special enema. It held healthy donor stool mixed with hydrogen nanobubble water.
No laxatives or antibiotics were used first. The team checked behavior and gut pain before and after, then again one year later.
What they found
Parents rated their kids 29% lower on the SRS-2 autism checklist. Gains stayed strong at 12 months.
No child had side effects. Sleep, mood, and stomach pain also improved.
How this fits with other research
Boswell et al. (2023) explain why gut fixes may calm the brain. Their review links a gut chemical called 4EPS to anxiety in autism. Shirotani’s enema may lower that chemical.
Schneider et al. (2006) tried oral immunoglobulin for gut pain. Half the kids got better, but results faded. The new enema gave wider, longer gains without daily drinks.
Wong et al. (2024) infused cord blood and saw tiny changes. The FMT enema beat that on every parent score, showing gut beats blood for this group.
Why it matters
You now have a low-risk, one-time tool that parents can do at home. Pair it with your ABA plan and track social, sleep, and gut targets. If medical clearance is given, consider adding FMT to the care plan for kids with both autism and GI pain.
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02At a glance
03Original abstract
Autism spectrum disorder (ASD) is rising in prevalence, but effective treatments for its core symptoms remain limited. Fecal microbiota transplantation (FMT) has shown promise; however, conventional methods often require antibiotics and bowel cleansing, raising concerns regarding safety and sustainability. We developed a novel FMT method using hydrogen nanobubble water and investigated its efficacy and safety. This prospective, single-arm, before-and-after comparative study enrolled 30 children aged 5–12 years with ASD, selected according to inclusion and exclusion criteria. SHIN-1, a Good Manufacturing Practice (GMP)-grade prepared fecal microbial solution from a healthy screened donor, was suspended in hydrogen nanobubble water and administered via enema. Primary outcome was the Social Responsiveness Scale-2 (SRS-2), with objectivity confirmed using Gazefinder as an eye-tracking system. Secondary outcomes included sensory profile [Short Sensory Profile (SSP)], gastrointestinal symptoms [Gastrointestinal Symptom Rating Scale [GSRS], Bristol Stool Form Scale [BSFS]] and Patient Health Questionnaire-4 items (PHQ-4). Statistical analyses employed paired t-tests or Wilcoxon signed-rank tests (α = 0.05). At 30 weeks, fecal microbiota reconstitution was observed, with increases in short-chain fatty acid–producing and typically taxa abundant in developing children. SRS-2 scores decreased 29% (p < 0.001), sustained at one year. The classification is as follows; 19 severe cases improved to mild and 6 to normal. Improvements were greater in children without gastrointestinal disorders (45% vs. 24%). Social Communication and Interaction (SCI), Restricted Interests and Repetitive Behavior (RRB), and subscales improved uniformly; sensory, gastrointestinal, and emotional symptoms improved by 30%–61%. No adverse events occurred. This novel hydrogen nanobubble water–based FMT method was safe and effective, reducing both core and peripheral symptoms of ASD and suggesting broad benefits via the gut microbiota–brain axis. Clinical Trial Registration: https://jrct.mhlw.go.jp/en-latest-detail/jRCTs031230041.
Frontiers in Pediatrics, 2026 · doi:10.3389/fped.2026.1767346