Dose Escalation Trial of Traditional Chinese Medicine for Irritable Bowel Syndrome (TCM- IBS) (TCM-IBS)

Inclusion Criteria:

• Age 18- 75
• All IBS patients attending the Gastroenterology Clinic of the Prince Of Wales Hospital of Hong Kong.

• IBS diagnosed by Rome III criteria:

  • Recurrent abdominal pain or discomfort at least three days per month in the previous three months
  • Symptoms onset at least six months prior to diagnose

  • Pain or discomfort associated with two or more of the following:

    1. Improvement with defecation
    2. Onset associated with change in frequency of stool
    3. Onset associated with a change in form (appearance) of stool
• Normal colonic evaluation (colonoscopy or barium enema) in past 5 years
• No "global symptom improvement" as rated by patients (see below) at screening and during the two- week run- in period to baseline

• Normal full blood count, liver function test and renal function test.

  • Informed written consent for participation into study.
  • Ethical approval will be obtained from the Joint CUHK-NTEC Clinical Research Ethics Committee as well as the IRB of UMB.

Exclusion Criteria:

• Past or present history of organic disease of gastrointestinal tract (e.g. colorectal cancer, advanced colonic polyp, celiac disease, inflammatory bowel disease, peptic ulcer and previous gastrointestinal surgery). (Note: those with polyps removed during colonoscopy can be included, as long as no known polyps remained.
• Systemic diseases that cause diarrhea or constipation (e.g. thyroid disease, diabetic neuropathy)
• Lactose intolerance
• Severe liver disease (e.g. cirrhosis, chronic active hepatitis)
• Renal impairment (serum creatinine level > 150mmol/L)
• Women who are pregnant, lactating or not practicing proper contraception
• Known hypersensitivity to herbal medicine
• Concommitant use of prescription antidepressant medication
• Current alcoholism and drug use
• Current psychiatric illness or dementia
• Fever or severe illness at baseline (week 0).