Bowel cancer bleeding is mainly characterized by blood mixed with stool, and the blood carried in stool is usually dark red in color, like jam-like, rather than bright red blood or even blood dripping out as in the case of bleeding hemorrhoids. Very often, it is only sticky dark red or black blood on the surface of stool, and blood in stool is often mixed with fecal mucus or pus, and even blood clots or necrotic tissues can be seen, and this phenomenon of blood in stool does not necessarily occur every time you have a stool. Bowel cancer bleeding is essentially caused by tumor cells, as well as newborn small blood vessels in the tumor that are squeezed in the stool, resulting in cancer cells infiltrating the rectal mucosa, causing surface ulceration or physical shedding of the tumor’s own tissue. If the tumor is more distal, such as bleeding in the ascending colon or even in the ileocecal region, the patient may even have black stool.