By Bob Condor

It’s easy for some doctors to completely dismiss colon cleansing as an option for someone struggling with digestive issues or as a preventive health measure. “There’s no research to support it” is a common reply, and that’s without any medical badmouthing.

While American research is thin, the enterprising doctor will acknowledge that scientific studies about colon irrigation—another term is colonic therapy—are more accessible in European research literature. One example: In a 2005 Netherlands study of individuals with …