The present study evaluated the safety and effectiveness of polyethylene glycol (PEG) laxative in 23 patients reporting a history of constipation.

After a 7-day placebo control period, it randomized the patients into a double crossover placebo trial versus 17 g of PEG daily for four days. It directed Patients to maintain a stool diary.

The study observed that-

• Daily ingestion of a 17 g dose of PEG increases mean daily bowel movement frequency to once per day by the last seven days of the 14-day treatment period.
• This improvement was significant over the placebo, which provided about one bowel movement every two days during the last week of therapy.
• PEG treatment improved patient diary ratings of related subjective symptoms over placebo.
• Both investigators and patients ranked PEG therapy superior to placebo.
• Participants displayed no clinically significant changes in blood chemistry, complete blood count (CBC), or urinalysis.

This study proves that daily therapy with 17 g of PEG laxative for 14 days significantly improves bowel movement frequency in constipated patients by the second week of treatment.

Source: Cleveland MV, Flavin DP, Ruben RA, Epstein RM, Clark GE. New polyethylene glycol laxative for treatment of constipation in adults: a randomized, double-blind, placebo-controlled study. South Med J. 2001 May;94(5):478-81. PMID: 11372795.