A Multi-center, Randomized, Double-blinded, Placebo-controlled Human Study to Evaluate the Efficacy and Safety of probiotic mixture(®GI Flora) in Subjects with Irritable Bowel Syndrome.

Regimen: 6 probiotics mixture >10^9/D for 8 weeks

Primary variable: visual analogue scale(VAS) assessment for abdominal pain

Secondary variable:

1. change of VAS score for abdominal pain/discomfort after 4/8-week treatment
2. daily symptom score for bloating, defecation discomfort(strain/urgency/incomplete evacuation), flatulence , feces shape, frequency of bowel movements

Inclusion Criteria:

• Irritable bowel syndrome patients according to Rome III criteria
• Recurrent abdominal pain or discomfort for at least 3 days per month in the last 3 months associated with at least 2 of the following characteristics: a) improvement with defecation; b) onset associated with a change in the frequency of stool; c) onset associated with a change in form (appearance) of stool.

Exclusion Criteria:

• Intolerable or hypersensitive to GI Flora.
• Patients with active colon diverticulitis.
• History of GI surgeries except hernia repair, appendectomy, primary closure due to perforation.
• History of inflammatory bowel disease, malignancy requiring surgery or chemotherapy or radiation within 5 years.
• Patient has any condition that, in the opinion of the Investigator, would compromise the well-being of the patient or the requirements of the study.