The colon is the organ that processes the products of digestion, stores them, and arranges evacuation at a suitable time and place. It is the home for trillions of microbes that serve multiple functions, affecting many of the other organs in the body. In fact, a person’s health is determined to a significant extent by the health of the colonic microbiome. So, stool, the dry weight of which is over 90% microbes, is the normal and desired content of the colon. Treatments that disturb the colonic microbiome, such as antibiotics, and, yes, colonic lavage, can be harmful by killing or removing the normal microbiome, by promoting pathogenic microbes, or by disturbing the complex interactions of normal microbes with the rest of the body.