<p>Lactulose is a synthetic disaccharide. Lactulose is metabolized in the colon by the saccharolytic bacteria, producing low molecular weight organic acids (mainly lactic acid), which lowers the pH of the colon contents, promote the retention of water by an osmotic effect; thus increasing peristaltic activity. Lactulose is minimally absorbed; therefore, the pharmacokinetics of the absorbed material are not relevant to the principal therapeutic action.</p>