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

This study is being done to see if St. John's wort helps people with irritable bowel syndrome, otherwise known as "IBS". St. John's wort is a herbal supplement derived from the St. John's wort plant. It has been shown to be helpful in several medical conditions such as depression as well as other pain syndromes.

Eligibility criteria:

1. Established diagnosis of IBS
2. 18-70 years of age

4) U.S. resident 5) English-speaking (able to provide consent and complete questionnaires) 6) Able to participate in all aspects of the study

You will be asked to do the following:

* Undergo a screening interview and physical examination
* Take a urine pregnancy test (if applicable)
* Take a study pill twice daily for 12 weeks(3 months)
* Complete daily symptom diaries and bi-weekly questionnaires for 12 weeks.
* Complete a questionnaire at 6 months after the active phase of the study is over.

Eligibility Criteria:
Inclusion Criteria:

* Established diagnosis of IBS
* Meet Rome II diagnostic criteria for IBS
* 18-70 years of age
* U.S. resident
* English-speaking (able to provide consent and complete questionnaires)
* Able to participate in all aspects of the study

Exclusion Criteria:

* Known alternative/concurrent gastrointestinal diagnosis (e.g. Crohn's disease, ulcerative colitis, microscopic colitis, celiac sprue, chronic pancreatitis or pancreatic insufficiency, scleroderma, chronic intestinal pseudo-obstruction, bacterial overgrowth, recent (\<6 months) intestinal bacterial/protozoal/ parasitic infections, HIV, fecal incontinence, small bowel or colonic resection, pelvic floor dysfunction, paraplegia or quadriplegia)
* Current symptoms of severe depression, as measured by Center for Epidemiological Studies Depression Scale (CES-D) score
* Mental retardation or any condition requiring a legal guardian
* Current or past history of psychotic disorder (schizophrenia, bipolar disorder)
* Recent or current use (within past 30 days) of select mood or pain or symptom-altering medications:

  * benzodiazepine use
  * substance abuse
  * narcotic use
  * antihistamine use
  * barbiturates
  * zaleplon (Sonata)
* Recent or current use (within past 30 days) of drugs that interact with SJW:

  * antidepressants or antipsychotics
  * tramadol (Ultram)
  * sumatriptan (Imitrex)
  * digoxin (Lanoxin)
  * anticonvulsants (e.g. carbamazepine or phenytoin)
  * immunosuppressants: cyclosporine and tacrolimus
  * HIV protease inhibitors (e.g. indinavir), non-nucleoside reverse transcriptase inhibitors (e.g. nevirapine)
  * warfarin (Coumadin)
  * theophylline
  * chemotherapy
  * sulfa-containing drugs
  * piroxicam (Feldene)
  * simvastatin (Zocor)
  * sibutramine (Meridia)
  * verapamil (Calan or Isoptin)
* Planned surgery (especially transplant) or anesthesia exposure during trial
* Known photosensitivity or planned photodiagnostic or phototherapy procedures
* Are pregnant, lactating, likely to become pregnant during medication phase and not willing to use a reliable form of contraception (barrier contraceptives, diaphragm, injections, intrauterine device, surgical sterilization, and abstinence)
* Recent or current use (within 30 days) of SJW, other herbal products for IBS, investigational drug use
* Known allergy to SJW
* Significant acute or chronic progressive neurologic, hepatic, renal, cardiovascular, respiratory or metabolic disease
* Recent history of alcohol or substance dependence use or abuse
* Another household member or relative participating in the study
* Professional drivers or operators of heavy machinery
* Major cardiovascular events in the last 6 months
* Use of IBS-specific drugs such as tegaserod (Zelnorm) and Lotronex (Alosetron) (within 30 days)