<Li> Internal hemorrhoids are covered by a layer of mucosa and epithelium, making them more likely to bleed, but typically do not cause pain . </Li> <Li> External hemorrhoids are less likely to bleed, they are covered by a different type of epithelium (squamous) but can cause significant pain as a result of thrombosis of the blood vessels within them . </Li> <Li> Polypectomy during a colonoscopy can lead to a small amount of bleeding seen in the stool after the procedure </Li> <Ul> <Li> Blood in the diet, for example, the traditional diet of the Masai includes much blood drawn from cattle . </Li> </Ul>

The red colour of blood is due to wha