Suffering a slipped or herniated disc is no joke. It can be excruciatingly painful and, in severe cases, it requires spine surgery and months of recovery. But for one chiropractor in Malaysia, fixing a slipped disc is as easy as knocking it back into position with a hammer.

Md Rosdi Hasan has a very unconventional way of dealing with slipped discs and back pain in general. Instead of relying on MRIs or X-rays to diagnose his patients’ back problems, he just uses his fingers to check if all the bones and vertebrae are in the right place, and draws a diagram of all the discs directly on the back of his patients, with a black marker. Once he learns everything he needs to know, Hasan grabs a hammer and a piece of wood and starts knocking the discs back into place.

Watching Rosdi Hasan taking a hammer to his patients’ spine like it’s no big deal is painful to watch, especially knowing that it could leave them paralyzed, but he claims no one has ever had any problems after his treatment. In fact, he is so proud of his method that he regularly posts videos of his “spinal tap” routine on his Facebook page. Some of them have tens of thousands of views, and despite the obvious joke comments, some people actually believe he can fix their spine problems.

One of Hasan’s videos went viral in Malaysian media back in March, and left actual doctors horrified. “Slipped discs CANNOT be treated by knocking,” Dr. Mahyuddin, an orthopedic surgeon, wrote on his Facebook page. “You can’t ‘see’ a slipped disc without an MRI or X-Ray.”

Mahyuddin also warns people willing to go under Rosdi Hasan’s hammer that his marker drawings of spinal discs on patients’ back are completely inaccurate and that a single wrong tap could leave them paralyzed.

Hasan obviously doesn’t agree, saying that it’s conventional doctors that actually do more harm than good.