Probiotic supplements improve IBS symptoms through manipulation of the gut microbiota. Metabolites derived from microbiota metabolism and host-microbiota co-metabolism have an impact on host intracellular signalling pathways. Although probiotic supplements improve IBS symptoms, the precise composition of probiotics that can achieve optimal response remains unclear. SMT04 (M3XTRA, GenieBiome Limited, Hong Kong, China) is a novel product that is commercially available as a dietary supplement in Singapore. It consists of a patented probiotics blend of 5 probiotics (3 Bifidobacteria and 2 Streptococci with 12.5 billion CFU in 1 sachet). Probiotics preparation that included varying composition of Bifidobacteria and Streptococci strains had previously demonstrated efficacy in achieving symptom improvement in IBS patients. Streptococcus thermophilus, a component of the blended probiotics, significantly improved intestinal functional barrier in healthy subjects. Thus there is potential for SMT04, a dietary supplement, to be a treatment option for IBS patients. This is a multi-centered trial, all data and samples from the study sites will be pooled together for analysis.

Probiotic supplements improve IBS symptoms through manipulation of the gut microbiota. Metabolites derived from microbiota metabolism and host-microbiota co-metabolism have an impact on host intracellular signalling pathways. Although probiotic supplements improve IBS symptoms, the precise composition of probiotics that can achieve optimal response remains unclear. SMT04 (M3XTRA, GenieBiome Limited, Hong Kong, China) is a novel product that is commercially available as a dietary supplement in Singapore. Probiotics preparation that included varying composition of Bifidobacteria and Streptococci strains had previously demonstrated efficacy in achieving symptom improvement in IBS patients. Streptococcus thermophilus, a component of the blended probiotics, significantly improved intestinal functional barrier in healthy subjects. Thus there is potential for SMT04, a dietary supplement, to be a treatment option for IBS patients.

The central hypothesis is that SMT04 can modulate gut microbiota and improve clinical symptoms of subjects with IBS. This pilot study will evaluate the effect of SMT04 on improving IBS related scores and the longitudinal changes in gut microbiome.

The investigators hypothesize that SMT04 can modulate gut microbiota and improve the clinical symptoms of subjects with IBS. This pilot study will examine the effect of SMT04 probiotic supplementation on symptoms in IBS patients. The Rome III rather than Rome IV IBS diagnostic criteria will be used as it is less restrictive with less temporal fluctuation, and hence will be more suitable in an exploratory study. The study will also analyse the longitudinal changes in gut microbiome composition to correlate clinical outcomes with pathophysiological changes. This is a multi-centered trial, all data and samples from the study sites will be pooled together for analysis. If this pilot study demonstrates potential beneficial effect, the investigators will conduct a more definitive randomized controlled trial.

Inclusion Criteria:

• Male or female, aged from 21 years to 70 years old

• Meet the criteria of the Rome-III-definition of IBS with diarrhoea or mixed subtypes, or functional diarrhoea Rome-III-definition: Abdominal pain or abdominal discomfort on minimum of three days per month during the last three months, starting at least six months ago, and a minimum of two of the following criteria:

  • Improvement of symptoms after defecation
  • Start of symptoms in association with a change in stool frequency
  • Start of symptoms in association with a change in stool consistency Subtype of IBS-D which requires more than 25% of the participant's stools to be loose and less than 25% hard and lumpy; subtype of IBS-M which the participant's stools must be both hard and lumpy, as well as loose in consistency at least 25% of the time. Functional diarrhoea: The experience of loose or watery stools without pain occurring in at least 75% of bowel movements for at least three months over the last six months.

• Have the latest negative colonoscopy result within five years

• Literate and can complete questionnaire

• Written informed consent is obtained

Exclusion Criteria:

• Known inflammatory bowel disease, lactose intolerance or other malabsorption syndromes, celiac disease, diabetes mellitus, thyroid dysfunction, cancer, immunodeficiency, autoimmune diseases, severe hepatic or renal insufficiency, other explainable causes of abdominal pain, diarrhoea or constipation
• Known operations involving small intestines and large intestines; or history of appendectomy, hysterectomy, and cholecystectomy in last 6 months.
• Known severe mental illnesses; unstable type or dose of psychiatric drugs within the last 3 months that will affect their judgement of study participation.
• Evidence of active infection at the time of inclusion
• History of use of prebiotics, probiotics, antibiotic therapy or anti-inflammatory drugs within the last 2 weeks
• Known current pregnancy or breast-feeding female