In a new case study, Irish doctors report the baffling case of a 33-year-old man who injected his own semen intravenously for a year and a half, a self-developed “cure” intended to treat his chronic back pain. It does not appear to have worked.

After reportedly injecting semen into his arm every month for 18 months, the man finally sought medical attention—but not for his arm. The patient instead complained of “severe, sudden onset lower pack pain,” having lifted a “heavy steel object” three days beforehand. During his checkup, the doctor found a patch of red swelling on his right forearm, after which the man admitted he’d been injecting himself with his own semen using a hypodermic needle he purchased online.

“This is the first reported case of semen injection for use as a medical treatment,” the doctors at Adelaide and Meath Hospital in Ireland wrote in the case study, titled “‘Semenly’ Harmless Back Pain: An Unusual Presentation of a Subcutaneous Abscess,” published in the Irish Medical Journal.

The swollen region grew and hardened around the area on his arm where he’d injected his semen, and an x-ray revealed an area of trapped air beneath the man’s skin. The doctors immediately hospitalized the patient, treating him with an intravenous antimicrobial therapy. After the patient’s back pain improved, he discharged himself.