If it is fresh blood in the stool, it is possible that the lesion is located near the rectum and anus. If it is dark red blood, it is likely that the lesion is located more distant, such as bleeding from the sigmoid colon, descending colon or ascending colon, transverse colon and so on, all of which may result in dark red blood. The common causes of bloody stools are anal fissures, external hemorrhoids, internal hemorrhoids and rectal tumors. If blood in the stool is accompanied by anal pain, it may be an anal fissure or external hemorrhoids. If the stool is not accompanied by anal pain, it may be internal hemorrhoids or rectal tumor, plus if there is a weight change in the recent past, such as weight loss in recent months, it may be a rectal tumor. It is recommended to visit the hospital, preferably to do a colonoscopy to exclude rectal tumors, because most rectal tumors are malignant and the prognosis is not good.