Consecutive patients of both sexes, age more than 18 years attended the outpatient department of Gastroenterology meeting the inclusion Criteria of IBS-C will be initially enrolled for the study. Their clinical history, examination \& initial investigations with Complete Blood Count , C-Reactive Protein, Tissue Transglutaminase antibody, Oral Glucose Tolerance Test, Thyroid Stimulating Hormone will be done from respected department of BSMMU. Report will be noted in the standard data sheet. Any alternative diagnosis if proven by clinical examination or laboratory investigation will be excluded from the study. All participants will be advised to maintain their usual dietary practices throughout the study. The subject will be recruited according to sample size. Total study population will be divided in to Prucalopride and placebo group. An independent treatment code will be generated and allocated according to sample size in each group. Randomization into two groups will be performed by lottery. The independent treatment codes and allocation will be maintained, which will be locked until all analyses will have been completed. Thus, the clinical trial will be performed double-blind with all patients and investigators will unaware of which treatment is allocated.

One group will receive tab Prucalopride 2 mg once daily 30 minute before breakfast, while the other group will receive identical looking placebo one tab once daily at same time. The tablets will be administered for a total of 6 weeks. Before starting treatment each individual will undergo a baseline assessment during which demographic data, base line investigations, IBS symptoms by IBS-SSS and QOL data will be recorded. Patients will be followed-up at 2 weeks, then at 6 weeks by IBS-SSS questionnaire and IBS-QOL questionnaire. Patients will be asked to return with the strips of the ingested drugs at the end of the treatment to count \& ensure compliance. Any adverse effect due to drugs will also be monitored by base line ECG, calculation of corrected QT interval and ECG monitoring (2 weeks and 6 weeks) during the course of treatment. Any adverse event will be responded quickly and documented at the same time.

IBS-SSS is a 5 item tools. It is primarily a measure of IBS symptoms including abdominal pain and distension as well as bowel satisfaction. This scale evaluates IBS symptoms: abdominal pain, abdominal distension, stool frequency and consistency and interference with life in general. The IBS-SSS calculates the sum of these 5 items scored on a visual analogue scale from 0-100. Determination of severity of each symptom is determined by the patient. The nature of the items on IBS-SSS is appropriate to be used in clinical trials. The items are summed and thus the total score can range from 0 to 500 points. IBS severity has the following defined ranges: mild 75-174, moderate 175-300, and severe \> 300.

The IBS-QOL questionnaire is a 34-item instruments which assess QOL impairment due to IBS symptoms. Each item is scored on a five-point scale (1 = not at all, 5 = extremely) that represents one of eight dimensions (dysphoria, interference with activity, body image, health-related worries, food avoidance, social reactions, sexual dysfunction, and relationships). After scoring by the patient, responses will be transformed to reverse code system (5= not at all, 1= extremely). Items are scored to derive an overall total score of IBS related QOL. To facilitate score interpretation, the summed total score is transformed to a 0-100 scale ranging from zero (poor QOL) to 100 (maximum QOL). The QOL instrument will be given to each patient before treatment is started. The patient will complete the form according to schedule and all data will be recorded and entered onto a data sheet.