Honestly. I think they are quacks. No scientific evidence supports the alleged benefits of colon cleansing, and it has no known medical value and risks damage to the rectum or bowel.
They give enemas. Colon irrigation involves irrigating a solution into the colon through the rectum with the presumptive goal of eliminating toxins. This practice dates back to ancient egypt. The traditional medical community has not embraced this for lack of scientific studies or evidence to support its clinical value.