Human Safety Trial Tested Rectal Oxygen Ventilation
Researchers explored whether a specialized liquid could deliver oxygen through the gut in a small, early-phase safety study.
Updated on Oct. 14, 2026 in Asthma
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A 2025 safety trial involving 27 healthy men examined whether perfluorodecalin could be safely retained in the gut. The study aimed to assess human tolerance for a novel enteral ventilation technique that could one day provide alternative oxygen delivery.
Why it matters
This research explores a potential emergency method for delivering oxygen when traditional breathing support is unavailable or difficult. Understanding whether the human body can safely tolerate rectal administration is a preliminary step toward developing new clinical options.
In a human safety trial published in 2025, 27 healthy men received rectal doses of oxygen-free perfluorodecalin ranging from 25 to 1,500 milliliters. Researchers observed no clinically significant changes in liver or kidney markers, though 20 participants retained the full dose.
The players
Nagoya University
A Japanese research institution that provided the lead investigators for this enteral ventilation safety trial.
Cincinnati Children's Hospital Medical Center
A pediatric research facility whose affiliated researchers contributed to the development and study of this technology.
University of Galway
An Irish university that provided the consulting lung specialist expertise for this research project.
EVA Therapeutics
The medical company that funded the safety trial investigating alternative oxygen delivery methods.
The details
The procedure involves holding oxygen-free perfluorodecalin in the rectum for up to one hour. While this trial focused on the safety and retention of the liquid, the technology relies on the gut's ability to facilitate gas exchange. Future research intends to use fully oxygenated perfluorodecalin to determine if this mechanism can successfully increase blood oxygen levels in humans.
Timeline
2021: Research team demonstrated that mice and pigs could absorb rectal oxygen.
2023: Researchers found the technique increased oxygen levels in pigs for 30 minutes.
2024: The enteral ventilation concept was honored with an Ig Nobel Prize.
October 20, 2025: Findings from the human safety trial were released online.
December 12, 2025: Results from the human safety trial appeared in print.
Health Landscape
This study marks a transition for the development of enteral ventilation as it moves from animal models to preliminary human safety testing. The field is currently evaluating whether this mechanism can serve as a future alternative to conventional respiratory support.
This study remains in the early, preliminary safety-testing phase and has no current application for personal health management or home care. Future clinical developments in this area are worth monitoring if you or a family member manage chronic respiratory conditions with a physician.
The takeaway
This preliminary trial suggests that the human gut can safely retain perfluorodecalin, providing a foundation for future testing of oxygenated liquids. Continue to discuss any concerns regarding respiratory health or new treatment protocols with your pulmonologist.
Further reading
For broader context on respiratory health and emerging support technologies, visit our Asthma section.
Source note: This article includes information reported by Medical Daily.
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