Hold your cheeks together next time you go under the knife, because a squeaky-bottomed Japanese woman recently ended up with burns to her legs and waist after her fart caught fire during surgery.

According to the Japanese newspaper Asahi Shimbun, the lady was being treated back in April at the Tokyo Medical University Hospital, where doctors used a laser to perform a procedure on her cervix. A report into the incident, which was released last week, explains that the laser ignited the gases that leaked from her intestines, causing the fire.

“When the patient’s intestinal gas leaked into the space of the operation [room], it ignited with the irradiation of the laser, and the burning spread, eventually reaching the surgical drape and causing the fire,” the report said.

It also confirmed that no flammable materials were present in the operating theatre at the time of the blaze, and that all equipment used in the procedure was operating normally, making the ill-timed fart the only possible cause of the incident.

Farts contain a number of different gases that are released as by-products of our intestinal activities. Among these are hydrogen and methane, both of which are flammable and give our windy expulsions their combustible characteristics.

Few other details about the nature of the fire have been made available and, according to The Telegraph, the condition of the woman is not known.