title: A randomized, double-blind, placebo-controlled trial of St John's wort for treating irritable bowel syndrome.
abstract: OBJECTIVE
  St John's wort (SJW) is known to effectively treat patients with mild-to-moderate depression. Antidepressants are frequently used to treat irritable bowel syndrome (IBS). To date, no study that examines the efficacy of SJW in IBS has been carried out. The aim of this study was to evaluate the efficacy of SJW in IBS after 12 weeks.
  
  
  METHODS
  In this randomized, double-blind, placebo-controlled trial, 70 participants with an established diagnosis of IBS were randomized and assigned by concealed allocation to either SJW or placebo. Both treatment arms were balanced on symptom subtype. The primary end point was self-reported overall bowel symptom score (BSS) at 12 weeks. Secondary end points were individual BSS for diarrhea (D-BSS), constipation (C-BSS), pain or discomfort, and bloating; adequate relief (AR) of IBS on at least 50% of the last 4 weeks of therapy; and IBS quality-of-life score at 12 weeks.
  
  
  RESULTS
  In all, 86% of the participants were women, and the median age was 42 years. Overall, 29% had C-IBS, 37% D-IBS, and 31% had mixed IBS. Both groups reported decreases in overall BSS from baseline, with the placebo arm having significantly lower scores at 12 weeks (P=0.03) compared with SJW. These patterns of improvement were mirrored in the secondary end points with the placebo group faring better than the SJW-treated group, with significant differences observed at week 12 for D-BSS (P=0.03) and percent with AR (P=0.02). A similar proportion of subjects in each treatment group (SJW: 51% vs. placebo: 54%) believed that the study drug they received decreased IBS life interferences (P=0.79).
  
  
  CONCLUSIONS
  SJW was a less effective treatment for IBS than placebo.
authors.affiliation: Mayo Clinic, Rochester, Minnesota 55905, USA. saito.yuri@mayo.edu
authors.forename: Yuri A
authors.initials: YA
authors.lastname: Saito
authors.forename: Enrique
authors.initials: E
authors.lastname: Rey
authors.forename: Ann E
authors.initials: AE
authors.lastname: Almazar-Elder
authors.forename: W Scott
authors.initials: WS
authors.lastname: Harmsen
authors.forename: Alan R
authors.initials: AR
authors.lastname: Zinsmeister
authors.forename: G Richard
authors.initials: GR
authors.lastname: Locke
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Talley
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D020902:Hypericum; D043183:Irritable Bowel Syndrome / Q000188:drug therapy*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008517:Phytotherapy / Q000379:methods*; D010919:Placebos; D011788:Quality of Life; D016896:Treatment Outcome
chemical_list: D010919:Placebos