In daily life, hemorrhoids and rectal cancer may have some identical or similar symptoms (such as blood in the stool), making some patients let down their own vigilance. In fact, blood in stool in colorectal cancer is slightly different from the condition of hemorrhoids. Hemorrhoids may occur in people of any age, while patients with rectal cancer are mostly middle-aged or elderly. Patients with hemorrhoids have blood in their stool, which is due to scraping the affected area during defecation, and most of the blood drips down with the stool and therefore does not mix with the feces, much less the presence of mucus. In contrast, the stool of rectal cancer patients is often mixed with blood, mucus and pus, and the habit of stool will change significantly. 1. Long-term constipation, one of the triggers of colorectal cancer Long-term constipation can lead to higher and higher concentration of carcinogens retained in the stool, and long-term contact between the intestinal wall and these carcinogens may be a triggering factor of colorectal cancer. Meanwhile, constipation is also one of the manifestations of colorectal cancer. As the left descending colon is narrow, so if the tumor is on this side, obstruction will often occur, resulting in constipation, and the doctor can basically determine which part of the colorectal cancer is in initially through questioning and finger diagnosis. 2.Change in bowel habit is also a precursor of rectal cancer Change in bowel habit should not be taken lightly as it may be a precursor of rectal cancer. The change of bowel movement includes many aspects, such as the usual dry bowel movement, but suddenly become thin or dry in these days; some people have a change in the number of bowel movements, from once a day to two or three times a day, or vice versa. In short, if there is abdominal discomfort, pain, local lump, feeling of urgency and heaviness, change of stool character and shape (from dry to thin, with mucus and blood or unformed stool, thin and flat), i.e., the stool is different from the usual pattern, you should go to hospital for specialist examination as early as possible. 3, prevention of rectal cancer, need to hold a scientific attitude In addition to regular colonoscopy screening, we must emphasize that the diet must be healthy, prohibit the consumption of five spice food, less pickled food, less glutinous food, less instant noodles and other industrial fried, puffed food, to develop good habits, do not smoke, do not drink; pay close attention to the stool characteristics, changes in bowel habits, when there is mucus stool, blood stool, black stool, unshaped stool, thin stool, stool, stool, stool, stool, stool, stool, stool, stool, stool, stool, stool. When there are symptoms such as mucus stool, bloody stool, black stool, unformed stool, thinning stool, changes in bowel habits, changes in the number of bowel movements, frequent diarrhea or difficulty in defecation, you must go to the hospital to see a doctor for examination.