Prescript-Assist probiotic-prebiotic treatment for irritable bowel syndrome: a methodologically oriented, 2-week, randomized, placebo-controlled, double-blind clinical study

Clin Ther. 2005 Jun;27(6):755-61. doi: 10.1016/j.clinthera.2005.06.005.


Background: The symptomatic efficacy of Prescript-Assist (Safer Medical, Inc., Fort Benton, Montana), a treatment combining probiotic and prebiotic components, has previously been evaluated clinically only in an open-label study in patients with various gastrointestinal conditions, including irritable bowel syndrome (IBS).

Objectives: This study was conducted primarily to compare the effects of Prescript-Assist with placebo in patients with a diagnosis of IBS. Toward this objective, a secondary methodologic goal was to determine the number and nature of symptom clusters ("subsyndromic factors") that characterize IBS.

Methods: This was a double-blind, placebo-controlled clinical study in which patients were randomly assigned to receive either Prescript-Assist one 500-mg capsule BID or 1 placebo capsule BID for 2 weeks. Thirteen IBS symptoms identified from the clinical literature were embedded in a larger research instrument. Using a scale from 0 to 5, patients rated the intensity of these symptoms for the 7-day period immediately before the start of treatment, at the end of each study week, and after each of the 2 subsequent weeks (during which all patients received open-label Prescript-Assist as part of a larger study evaluating methodologic approaches to enhancing assessments of medication efficacy/safety). The symptom-intensity data were subjected to maximum likelihood factor analysis with varimax rotation to identify any IBS subsyndromic factors, and the effect of treatment on each of the identified factors was evaluated using analyses of covariance with appropriate baseline-week assessments as covariate controls.

Results: The study included 25 patients with IBS (23 women, 2 men; age range, 20-70 years). Three subsyndromic factors were identified that together accounted for 60.2% of total IBS symptom variance: factor 1, general ill feelings/nausea; factor 2, indigestion/flatulence; and factor 3, colitis. Treatment with Prescript-Assist was associated with significant reductions in each of the subsyndromic factors. Factor 1 was significantly reduced by 0.345 standard score units (F(1,46) = 4.26; P = 0.042), factor 2 by 0.544 standard score units (F(1,46) = 7.83; P = 0.008), and factor 3 by 0.826 standard score units (F(1,46) = 10.20; P = 0.003).

Conclusions: This study identified 3 subsyndromic factors of IBS: general ill feelings/nausea, indigestion/flatulence, and colitis. In this methodologically oriented double-blind study in patients with IBS, combined probiotic-prebiotic treatment with Prescript-Assist was associated with significant reductions in these factors.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Administration, Oral
  • Adult
  • Aged
  • Capsules
  • Colitis / prevention & control
  • Double-Blind Method
  • Dyspepsia / prevention & control
  • Female
  • Flatulence / prevention & control
  • Humans
  • Humic Substances / analysis
  • Humic Substances / microbiology
  • Irritable Bowel Syndrome / pathology
  • Irritable Bowel Syndrome / therapy*
  • Male
  • Memory Disorders / prevention & control
  • Middle Aged
  • Multivariate Analysis
  • Nausea / prevention & control
  • Patient Selection
  • Probiotics / administration & dosage
  • Probiotics / therapeutic use*
  • Sleep Stages / drug effects
  • Time Factors
  • Treatment Outcome
  • Vomiting / prevention & control


  • Capsules
  • Humic Substances