Breathing through the gut: Study confirms treatment is well tolerated
Animal studies have shown that certain mammals – including mice, rats and pigs – can absorb oxygen through their intestines. This unusual concept even earned an Ig Nobel Prize in 2024. Until recently, however, it remained unclear whether the method could be applied to humans. That changed when an international team from the United States and Japan, led by Japanese stem cell researcher Dr. Takanori Takebe, successfully tested enteral ventilation in humans for the first time. The results of the phase 1 study were published on October 20, 2025, in the journal Cell / Med.
The study was conducted at Cincinnati Children’s Hospital (United States) and involved 27 healthy men aged 20 to 45. Researchers used perfluorodecalin (PFD), a liquid capable of binding exceptionally large amounts of oxygen – up to 500 milliliters of O₂ per liter. Already used in eye surgery and as a carrier in medical oxygen formulations, PFD was administered in gradually increasing doses to assess tolerability. Participants received between 25 and 1,500 milliliters of the liquid, with each dose remaining in the intestine for 60 minutes.
An important note: The PFD used in the study was not oxygenated, meaning it did not contain any added oxygen. The primary aim of this phase 1 trial was to assess the tolerability of administering the liquid rectally, rather than to evaluate its effectiveness in oxygen delivery.
No serious side effects – good tolerability confirmed
No serious side effects or toxic reactions were observed, even at the highest dose. About 59% of participants reported mild symptoms such as abdominal pain, flatulence or the urge to defecate – mainly at higher volumes. Four of the six participants in the highest-dose group ended their sessions early due to discomfort. However, laboratory results, blood pressure and organ function remained within normal ranges throughout the study. No PFD was detected in the blood, indicating that it was not absorbed through the intestinal lining. Despite these minor side effects, rectal administration of PFD was considered well tolerated.
Safety confirmed – therapeutic potential could be significant
All in all, the study confirms the safety of the procedure but cannot yet demonstrate any therapeutic benefit, as non-oxygenated PFD was used. Future research should investigate how much oxygen from oxygen-enriched PFD can be absorbed into the bloodstream through the intestinal lining. If therapeutic efficacy is confirmed, this could pave the way for a groundbreaking ventilation method – one that could be applied when conventional ventilation is too risky or not feasible, such as in cases of acute lung failure. It would offer a potential solution for critical situations that current medical approaches still struggle to manage.
