A pilot study on the role of the oxytocinergic system in gut microbiome composition in children with autism: baseline associations and effects of intranasal oxytocin.

This was a randomised controlled trial — people were assigned to treatments by chance, which is the most reliable way to tell whether a treatment itself caused a change.

The number of people who took part is not stated in this record, so the result cannot be judged on size.

The abstract does not include a conclusions section, so this page does not state what the researchers concluded.

This record does not state:

• the ages of the people who took part
• how long the study ran

This is a plain-language summary of one paper's abstract, not medical advice. Talk to your child's clinician before changing anything.

Journal: Brain, behavior, and immunity

Year: 2026

Design: Randomized Controlled Trial

Intervention: oxytocin

Co-occurring conditions: Dysbiosis

Authors: Evenepoel Margaux, Tuerlinckx Elise, Derrien Muriel, Moerkerke Matthijs, Prinsen Jellina, Vich Vila Arnau, Steyaert Jean, Daniels Nicky, Boets Bart, Raes Jeroen, Alaerts Kaat

Autistic children often experience behavioral difficulties alongside nutritional and gastro-intestinal (GI) problems, including gut dysbiosis. Recent research has highlighted important interactions between the oxytocinergic system and gut microbiome compositions, however, insights into how exogenous administration of oxytocin may influence GI health remain largely unexplored. Here, we first examined whether nutrition, GI symptoms and microbiome compositions vary in autistic versus non-autistic children, and how alterations link to clinical-behavioral difficulties and oxytocinergic signaling. Next, we examined the effect of a four-week intranasal oxytocin administration regimen on GI health/dysbiosis in autistic children enrolled in a randomized placebo-controlled trial. Compared to non-autistic children, autistic children consumed more soft drinks, and fewer vegetables and experienced abdominal pain more frequently over the past three months. Notably, epigenetic variations in the oxytocin receptor gene (OXTR) were associated with stool consistency, indicating that children with looser stools exhibited lower OXTR methylation levels, indicative of increased receptor expression. Additionally, a higher abundance of Romboutsia was associated with OXTR hypo-methylation and more anxiety-like behavior. In autistic children, the four-week oxytocin regimen had no effect on bacterial diversity but did modify stool consistency, leading to less dense stools with an overall more normal stool consistency, and an increased abundance of the potentially anti-inflammatory genus Fusicatenibacter. To conclude, this study provides novel insights into the role of the oxytocinergic system in GI symptoms and gut microbiome compositions in autistic children, and preliminary evidence suggesting a modulatory effect of exogenously administered oxytocin on these parameters.

Brain, behavior, and immunity, 2026

PMID 41941984

DOI 10.1016/j.bbi.2026.106579

This record was extracted from the paper's PubMed abstract and metadata. Full-text methods and risk-of-bias details were not reviewed.