This clinical study aims to investigate the effectiveness and safety of Gelsectan, a treatment containing xyloglucan, in adults diagnosed with diarrhea-predominant irritable bowel syndrome (IBS-D) in Vietnam. IBS-D is a common digestive disorder that causes frequent diarrhea along with abdominal pain and bloating, significantly affecting patients' daily life and wellbeing.

The main goal of the study is to determine whether Gelsectan can reduce the severity of symptoms such as diarrhea, abdominal discomfort, and bloating, and improve patients' quality of life. Participants will be randomly assigned to receive either Gelsectan alone, Gelsectan combined with an antispasmodic medication, or antispasmodic medication alone. The treatment will last for two months, with regular monitoring of symptom changes and any side effects.

The investigators hypothesize that Gelsectan treatment will lead to better symptom relief and quality of life compared to standard antispasmodic treatment. The study will also carefully observe the safety profile of Gelsectan during the treatment period.

Results from this study will provide important information about the potential benefits and risks of Gelsectan for Vietnamese patients with IBS-D and may contribute to improving treatment options for this condition in Vietnam.

Diarrhea-predominant irritable bowel syndrome (IBS-D) is one of the most common subtypes of IBS, accounting for approximately 30-40% of all IBS cases. In developed countries, xyloglucan-the main component of Gelsectan-has been demonstrated in various studies to be a promising therapeutic option for IBS-D. Xyloglucan forms a biofilm that protects the intestinal mucosa, reduces permeability, and helps prevent the effects of inflammatory agents and functional disturbances in the gut. Clinical studies have shown that xyloglucan not only alleviates symptoms such as diarrhea, abdominal pain, and bloating, but also restores intestinal function and significantly improves the quality of life in patients with IBS-D. IBS-D is also prevalent in Vietnam; however, there is currently no published research evaluating the use of Gelsectan for the treatment of this condition in the Vietnamese population.

This study aims to evaluate the efficacy of Gelsectan in the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D) by assessing improvements in diarrhea, bloating, abdominal pain, and quality of life after 1 and 2 months of treatment. Additionally, the study investigates the safety profile of the product based on the frequency and severity of adverse events recorded throughout the intervention period.

This study is an open-label, randomized controlled clinical trial conducted at the Gastroenterology Outpatient Clinic of the University Medical Center Ho Chi Minh City, from April 2025 to April 2026. The study population includes patients aged 18 years and older, diagnosed with diarrhea-predominant irritable bowel syndrome (IBS-D) according to the Rome IV criteria.

After providing informed consent, participants will be randomly assigned to one of three intervention groups: (1) Gelsectan monotherapy, (2) Gelsectan combined with an antispasmodic agent, and (3) antispasmodic therapy alone. The intervention period lasts two months, with clinical assessments conducted at baseline, after one month, and after two months of treatment. The variables recorded include clinical remission status, number of daily diarrhea episodes, intensity of abdominal pain and bloating, and quality of life scores. Adverse events will be continuously monitored and recorded according to their severity and their relationship to the intervention.

The results of this study will provide additional clinical evidence on the efficacy and safety of Gelsectan in the treatment of IBS-D, contributing to the expansion of therapeutic options in Vietnam. The application of Gelsectan may offer practical benefits in alleviating symptoms, improving patients' quality of life, and reducing healthcare costs associated with the management and treatment of IBS-D.

Inclusion Criteria:

• Age ≥ 18 years

• Diagnosis of IBS-D based on the Rome IV criteria,8 including:

  • Recurrent abdominal pain occurring at least one day per week in the last three months, associated with at least two of the following: related to defecation, associated with a change in stool frequency, or associated with a change in stool form. These criteria must have been present during the last three months, with symptom onset at least six months prior to diagnosis;
  • More than 25% of bowel movements with stool types 6 or 7 and less than 25% with stool types 1 or 2 according to the Bristol Stool Form Scale.

• Signed informed consent for study participation

Exclusion Criteria:

• Pregnant or breastfeeding women
• Known allergy to any component of the study medication
• Diagnosed with diabetes mellitus
• Patients with severe comorbidities or psychiatric disorders that impair their ability to complete questionnaires or attend follow-up visits