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

Eligibility criteria:

• Established diagnosis of IBS
• 18-70 years of age

• 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.

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)