Patients in the treatment arm with weight between 35 kg to 50 kg will receive 50 mg capsule of curcumin twice a day (maximum dose 2.8 mg/kg/day, which is within the GRAS approved dose) and those over 50 kg in weight will receive three curcumin capsules a day (maximum dose 3 mg/kg/day, within GRAS recommended dose). Study duration will be 8 weeks.

Patients in the placebo arm will receive a capsule which has similar size, shape and color of the curcumin capsule. The placebo capsule will contain inert food powder. Study duration will be 8 weeks.

The curcumin food supplement will be administered in the form of capsules. Participants in the treatment arm will take 50 mg twice or three times a day, depending on their body weight. Participants will take the curcumin capsules for eight weeks.

To study the alteration in gut microbiota with 8-week curcumin dietary supplementation in children with IBS between the ages of 10 yrs to 18 yrs

To compare the GI symptoms at baseline and after 8-weeks of curcumin dietary supplementation we will be using a previously validated Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) questionnaire (Francis CY, Morris J, Whorwell PJ. The irritable bowel severity scoring system: a simple method of monitoring irritable bowel syndrome and its progress. Aliment Pharmacol Ther 1997; 11(2): 395-402). This questionnaire measures symptom severity and includes a scale of "none" to "very severe" or "very happy to very unhappy" or "not at all" to "completely" as well as "often/occasionally/never." The maximum achievable score is 500 and mild, moderate and severe cases are indicated by scores of 75 to 175, 175 to 300 and >300 respectively. Higher scores means worse outcome and vice versa. At the end of the 8-weeks curcumin supplementation any absolute or relative decrease in the total score in comparison to baseline will considered as improvement in outcome.