Psyllium is superior to docusate sodium for treatment of chronic constipation

Aliment Pharmacol Ther. 1998 May;12(5):491-7. doi: 10.1046/j.1365-2036.1998.00336.x.


Background: Stool softening is a physician's first step in the management of chronic constipation.

Aim: To compare stool softening (stool water content) and laxative efficacy of psyllium hydrophilic mucilloid vs. docusate sodium.

Methods: The multi-site, randomized, double-blind, parallel-design study of 170 subjects with chronic idiopathic constipation involved a 2-week baseline (placebo) phase followed by 2 weeks of treatment. The treatment phase compared psyllium (5.1 g b.d.) plus docusate placebo to docusate sodium (100 mg b.d.) plus psyllium placebo. Stools were collected and assessed.

Results: Compared to baseline, psyllium increased stool water content vs. docusate (psyllium 2.33% vs. docusate 0.01%, P = 0.007). Psyllium also increased stool water weight (psyllium 84.0 g/BM; docusate 71.4 g/BM; P = 0.04), total stool output (psyllium 359.9 g/week: docusate 271.9 g/week; P = 0.005), and O'Brien rank-type score combining objective measures of constipation (psyllium 475.1; docusate 403.9; P = 0.002). Bowel movement (BM) frequency was significantly greater for psyllium (3.5 BM/week) vs. docusate (2.9 BM/week) in treatment week 2 (P = 0.02), with no significant difference (P > 0.05) between treatment groups in treatment week 1 (3.3 vs. 3.1 BM/week).

Conclusion: Psyllium is superior to docusate sodium for softening stools by increasing stool water content, and has greater overall laxative efficacy in subjects with chronic idiopathic constipation.

Publication types

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

MeSH terms

  • Adult
  • Aged
  • Cathartics / therapeutic use*
  • Chronic Disease
  • Constipation / drug therapy*
  • Dioctyl Sulfosuccinic Acid / therapeutic use*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Psyllium / therapeutic use*


  • Cathartics
  • Dioctyl Sulfosuccinic Acid
  • Psyllium