Hello and welcome to HCM. Thank you for your query. The first and foremost thing you need to know is the fact that IBS includes two conditions. They are: ulcerative colitis(UC) and Crohn s disease (CD). Now let me explain the presence of blood, that you saw, and why this happens. In UC, when the whole colon is involved, there is a slowly progressing ulcer, thus, the body s defense mechanism tries to repair that ulcer, resulting in the development of pseudo polyps. This ulcer moves in a horizontal direction, damaging blood vessels, which results in blood seen in the diarrhea intermittently. Whereas in Crohn s disease (CD), there is an apthous ulcer which moves in a vertical fashion, and once this ulcer reaches sub-mucosal blood vessels, blood is seen in the stool. So the blood that you have observed is part of the development of the condition that you have been diagnosed with. You could inform your treating doctor, who will then know the stage of your condition. Just to keep him well informed. I hope I have explained this well enough. I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you. Best wishes.