A brief review is made of trials which used low doses of polyethylene glycol (13-30 g/day) solutions (125-500 ml/day) in the treatment of chronic functional constipation. Most of these were short-term studies, and confirmed that polyethylene glycol solution increased bowel frequency, improved defaecation and decreased stool consistency. Three studies reported that polyethylene glycol electrolyte solution accelerated transit through the large bowel. One long-term study observed remission of constipation-related symptoms in more than 70% of the polyethylene glycol electrolyte solution treated patients, and the efficacy of the treatment was maintained over a 6-month period, despite progressive reduction of daily dosage.