Hi, As most of the organic problems are ruled out by above investigations, the history is very much suggestive of irritable bowel syndrome also known as IBS. Most of the times it is a benign disease which needs some lifestyle modifications like including more fibres in diet, taking a judicious amount of water especially in those having constipation, and reducing caffeine and legumes. Sometimes psychological therapies like cognitive behavioural therapy and relaxation therapies are also helpful. When symptoms aren t controlled with above-mentioned measures, then drugs can be recommended accordingly whether constipation or diarrhoea is the predominant symptom. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Muhammad Zahir Shah, Internal Medicine Specialist