A randomized, placebo-controlled, multicenter study of the safety and efficacy of a new polyethylene glycol laxative

Am J Gastroenterol. 2000 Feb;95(2):446-50. doi: 10.1111/j.1572-0241.2000.01765.x.


Objective: This study was designed to determine the efficacy and safety of a new laxative, Braintree polyethylene glycol (PEG) laxative (Miralax, Braintree Laboratories, Braintree, MA).

Methods: This investigation was designed as a placebo-controlled, blinded, randomized, multicenter parallel trial. Study subjects were constipated but otherwise healthy outpatients who had < or =2 stools during a 7-day qualification period. Braintree PEG laxative 17 g or dextrose placebo p.o. in 8 oz of water for a 14-day treatment period. A diary recorded each bowel movement and subjective symptoms of stool consistency, ease of passage, cramps, and flatus. CBC, blood chemistries and urinalysis were performed before and after the treatment period.

Results: There were 151 randomized subjects, 131 female and 20 male. An increase in bowel movement frequency was observed with the PEG laxative as compared to placebo (p<0.001), with the greatest difference in efficacy in wk 2 of treatment (p<0.001). By wk 2 of treatment, on average, placebo subjects had 2.7 bowel movements/wk and PEG-treated study subjects had 4.5 movements/wk (p<0.01), or more than one bowel movement every 2 days. Investigator (p<0.005) and patient (p<0.001) subjective assessment of perception of treatment effectiveness, and patient evaluations of stool consistency and passage showed significant improvement in the active treatment group (p<0.001). There were no significant differences in laboratory changes or adverse experiences recorded between groups.

Conclusion: Braintree PEG laxative is safe and effective in the short term for the treatment of constipation.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cathartics / therapeutic use*
  • Colic / etiology
  • Constipation / drug therapy*
  • Defecation / drug effects
  • Feces
  • Female
  • Flatulence / etiology
  • Humans
  • Male
  • Medical Records
  • Middle Aged
  • Patient Satisfaction
  • Placebos
  • Polyethylene Glycols / therapeutic use*
  • Safety
  • Single-Blind Method


  • Cathartics
  • Placebos
  • Polyethylene Glycols