Japanese researchers have taken a significant step toward proving that humans can breathe through their buttocks in emergency situations. A new clinical trial, published in the journal Med, tested the safety of delivering oxygen via the rectum in 27 healthy men.
The study builds on earlier work that earned the researchers an Ig Nobel Prize in 2024 for demonstrating that animals such as rodents and pigs can absorb oxygen through the rectum. The latest trial involved volunteers holding between 25 and 1,500 millilitres of a non-oxygenated perfluorocarbon liquid in their rectum for up to an hour.
Results showed no serious harmful effects, though participants receiving the highest volume reported abdominal bloating, discomfort, and some pain. Only seven of the 27 volunteers could not complete the full hour. The maximum tolerable dose was 1,000 millilitres.
Senior author Dr Takanori Takebe, an expert in organoid medicine at Osaka University and Cincinnati Children's, said: 'This is the first human data, and the results are limited solely to demonstrating the safety of the procedure and not its effectiveness. But now that we have established tolerance, the next step will be to evaluate how effective the process is for delivering oxygen to the bloodstream.'
The proposed method, called enteral ventilation, would use a highly oxygenated perfluorocarbon liquid that permeates intestinal walls into the bloodstream. The researchers hope it could serve as a last resort for patients with severe respiratory failure when conventional ventilation is unavailable.
