Various forms of colon cleansing were popular in the 19th and early 20th century. In 1932, Bastedo wrote in the
Journal of the American Medical Association about his observation of mucus masses being removed during a colon irrigation procedure: "When one sees the dirty gray, brown or blackish sheets, strings and rolled up wormlike masses of tough mucus with a rotten or dead-fish odor that are obtained by colon irrigations, one does not wonder that these patients feel ill and that they obtain relief and show improvement as the result of the irrigation." While colonic irrigation enjoyed a vogue in the early 20th century as a possible cure for numerous diseases, subsequent research showed that it was useless and potentially harmful. With the scientific rationale for "colon cleansing" disproven, the idea fell into disrepute as a form of
quackery, with a 2005 medical review stating that "there is no evidence to support this ill-conceived theory that has been long abandoned by the scientific community." Similarly, in response to claims that colon cleansing removes "toxins", Bennett Roth, a gastroenterologist at the
University of California, stated that "there is absolutely no science to this whatsoever. There is no such thing as getting rid of quote-unquote 'toxins.' The colon was made to carry stool. This is total baloney." Nevertheless, interest in colonic "
autointoxication" as a cause of illness, and in colonic irrigation as a cure, enjoyed a revival in
alternative medicine at the end of the 20th century. Though Anderson argues that his beliefs are backed by scientific research, his claims are primarily supported by
anecdotal evidence rather than
empirical data, and doctors have noted the absence of mucoid plaques. Anderson claims this is due to medical textbooks failing to cover the concept, which results in doctors not knowing what to look for. ==Medical evaluation==