Mechanisms of action of low doses of polyethylene glycol in the treatment of functional constipation.

Different doses of polyethylene glycol have different effects on intestinal function. In normal volunteers, low doses increase stool weight without modifying oro-anal transit time. In constipated patients, low doses decrease stool consistency, increase stool frequency, and facilitate stool evacuation without modifying stool weight and colonic transit time. Low doses of polyethylene glycol may be efficient in the treatment of functional constipation by effecting dilution water in the faeces and, thus, reducing stool consistency.