This is the mechanistic premise of the Battle Creek regimen: that the large bowel is a source of self-poisoning whose absorbed toxins drive chronic disease and shorten life. Kellogg set out the argument at book length in Autointoxication; or, Intestinal Toxemia (1919), and Mathias (2018) identifies that book as the bestselling vehicle through which he popularized the theory. The claim is classified as refuted and the endpoint as mechanism-only: no human lifespan endpoint was measured, and the proposed absorption mechanism does not operate as stated. Whorton (2000) records that experimental studies in the 1910s cast doubt on the possibility of bowel toxins leaching into the circulation, and that autointoxication faded from professional acceptance during the 1920s. The framework was discarded by mainstream medicine; modern microbiome research investigates gut-host interactions on a separate and independently evidenced basis and does not revive autointoxication as Kellogg stated it (Mathias, 2018).