The full title of an osteopath is “Doctor of Osteopathic Medicine.” From a quick Google search, “An osteopath is a licensed physician who practices medicine using both conventional treatments and osteopathic manipulative medicine”
Having been to one, I found the manipulation to be unhelpful. She quickly zoomed into the trouble spot, but the treatment did nothing for me. But at least it didn’t actively harm me. I later received proper medical treatment from a neurosurgeon and physical therapy, because that’s what I needed instead of a manipulation.