A Placebo-Controlled Trial of St. John's Wort for Irritable Bowel Syndrome

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00587860
Recruitment Status : Completed
First Posted : January 8, 2008
Results First Posted : March 1, 2010
Last Update Posted : March 9, 2010
Information provided by:
Mayo Clinic

Study Type: Interventional
Study Design: Allocation: Randomized;   Intervention Model: Parallel Assignment;   Masking: Triple (Participant, Care Provider, Investigator);   Primary Purpose: Treatment
Condition: Irritable Bowel Syndrome
Interventions: Drug: St. John's wort
Drug: Placebo

  Participant Flow

Recruitment Details
Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
Participants were identified through community, institutional advertisement,, through the IFFGD webpage as well as through the outpatient clinics beginning in February 2006. Participants who participated in previous IBS studies were also mailed a recruitment letter to ask if they would be interested in participating.

Pre-Assignment Details
Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
For this study, there was a 2-week screening and enrollment phase. During this period, participants were screened, a symptom questionnaire was completed, and there was a physician exam. After the in-person screening visit, a phone call was made prior to mailing the study materials to ensure the participant was still willing to participate.

Reporting Groups
St. John's Wort St. John's Wort, 450 mg twice a day
Placebo Placebo, twice a day

Participant Flow:   Overall Study
    St. John's Wort   Placebo
STARTED   35   35 
COMPLETED   30   30 
Lost to Follow-up                2                2 
Withdrawal by Subject                3                3 

  Baseline Characteristics

Population Description
Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
No text entered.

Reporting Groups
St. John's Wort St. John's Wort, 450 mg twice a day
Placebo Placebo, twice a day
Total Total of all reporting groups

Baseline Measures
   St. John's Wort   Placebo   Total 
Overall Participants Analyzed 
[Units: Participants]
 35   35   70 
[Units: Participants]
<=18 years   0   0   0 
Between 18 and 65 years   33   35   68 
>=65 years   2   0   2 
[Units: Years]
Mean (Standard Deviation)
 42.2  (14.34)   39.43  (11.26)   40.81  (12.87) 
[Units: Participants]
Female   30   30   60 
Male   5   5   10 
Region of Enrollment 
[Units: Participants]
United States   35   35   70 
Bowel Symptom Score (BSS) [1] 
[Units: Units on a scale]
Median (Full Range)
 (36 to 314) 
 (73 to 290) 
 (36 to 314) 
[1] The BSS is a five question, 100-mm visual analog scale of four IBS symptoms (pain/discomfort, bloating, constipation, and diarrhea), and an overall severity scale. The best possible value would be 0 (no symptoms) and the worst is 500 (severe symptoms). BSS was assessed on a bi-weekly basis.
Center for Epidemiologic Studies Depression Scale (CES-D) score [1] 
[Units: Units on a scale]
Median (Full Range)
 (0 to 26) 
 (0 to 32) 
 (0 to 32) 
[1] We measured CES-D Score at baseline as well as bi-weekly throughout the study. The CES-D is a self-reported 20 question survey designed to measure depressive symptomatology in the general population. The possible range of scores is zero to 60, with the higher scores indicating the presence of more symptomatology.
Irritable Bowel Syndrome - Quality of Life (IBS-QoL) [1] 
[Units: Units on a scale]
Median (Full Range)
 (4 to 62) 
 (0 to 79) 
 (0 to 79) 
[1] The IBS-QOL is a self-report quality-of-life measure specific to Irritable Bowel Syndrome (IBS) that can be used to assess the impact of IBS and its treatment. The IBS-QOL was measured at baseline, week 12 and week 24. The individual responses to the 34 items are summed and averaged for a total score and then transformed to a 0-100 scale for ease of interpretation with higher scores indicating better IBS specific quality of life.

  Outcome Measures

1.  Primary:   Overall Bowel Symptom Scores (BSS)   [ Time Frame: After 12 weeks of treatment ]

2.  Secondary:   Bowel Symptom Score (BSS) Amongst Subgroups   [ Time Frame: 12 weeks ]

3.  Secondary:   Adequate Relief ≤ 50% During the Last 4 Weeks of Therapy   [ Time Frame: Last 4 weeks of therapy ]

4.  Secondary:   Irritable Bowel Syndrome - Quality of Life (IBS-QoL) Score   [ Time Frame: 12 weeks of treatment ]

5.  Secondary:   Center for Epidemiologic Studies Depression Scale (CES-D) Score   [ Time Frame: 12 weeks ]

6.  Secondary:   IBS Symptoms Moderately or a Lot Better   [ Time Frame: 24 weeks ]

7.  Secondary:   Center for Epidemiologic Studies Depression Scale (CES-D) Score   [ Time Frame: 24 weeks ]

8.  Secondary:   Bowel Symptom Score (BSS) at 24 Weeks   [ Time Frame: 24 weeks ]

  Serious Adverse Events

  Other Adverse Events

  Limitations and Caveats

Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
  • A majority of the participants were local females with mild symptoms
  • The number of participants limits power of conclusions
  • We evaluated the efficacy of SJW in all subtypes of IBS not allowing specific conclusions regarding subtypes

  More Information

Certain Agreements:  
All Principal Investigators ARE employed by the organization sponsoring the study.

Results Point of Contact:  
Name/Title: Yuri A. Saito Loftus, M.D., M.P.H.
Organization: Mayo Clinic
phone: 507-284-5010

Responsible Party: Yuri A. Saito Loftus, M.D., Mayo Clinic Identifier: NCT00587860     History of Changes
Other Study ID Numbers: 132-06
First Submitted: December 27, 2007
First Posted: January 8, 2008
Results First Submitted: October 26, 2009
Results First Posted: March 1, 2010
Last Update Posted: March 9, 2010