Abstract The sections in this article are: Alimentary Excretion of Organic and Inorganic Substances Salivary Excretion Excretion From Respiratory to Gastrointestinal Tract Transfer of Foreign Compounds Into Gastric Contents Intestinal Excretion Pancreatic Excretion General Mechanisms of Biliary Excretion of Foreign Compounds Alimentary Excretion of Selected Pharmacological Agents Alimentary Excretion of Selected Environmental Agents Enteric Factors that May Modify Alimentary Excretion Mucosal and Hepatic Conjugation Presence of Bile Gut Bacteria and Enterohepatic Circulation Chelating Agents Concluding Remarks