Colorectal cancer is one of the most common malignant tumors with the highest incidence in China, ranking 4th among all malignant tumors, among which rectal cancer is the most common, accounting for about 60% of the overall cases. In early stage, colorectal cancer may have no obvious symptoms or patients only feel vague discomfort, but with the development of tumor, its symptoms will gradually worsen and even cause systemic toxic symptoms, such as indigestion, change of stool habit, blood in stool, abdominal mass, abdominal pain, intestinal obstruction, anemia and significant weight loss. So, what signals can be used to help diagnose and treat colorectal cancer in the early stage? Six signals 1. Change in stool habit This is a relatively important and obvious early signal to determine whether colorectal cancer is present. It is generally manifested as persistent constipation and diarrhea, or alternating diarrhea and constipation, or a feeling of incomplete stool, but there is no obvious reason to explain. 2, stool traits change stool thinning or with mucus or bloody mucus, or stool with obvious blood, or discharge of black stool, may also appear flattened stool shape, thinning, etc.. 3, systemic manifestations such as unexplained anemia, wasting, weakness or even hypothermia and other systemic symptoms. 4, abdominal masses A lump can be vaguely felt by pressing on the abdomen. 5.Impatient and heavy after defecation, or sometimes have the intention to defecate, but no stool is released, or after defecation always feel that there is still stool, but just can not be defecated, this is “urgent and heavy after”. 6, unexplained pre-poo or post-poo abdominal pain manifested as continuous or intermittent pain in fixed parts of the abdomen. If you have 1 or 2 of the above symptoms and they last for 3 days or even more than 1 week, you should seek professional medical examination immediately, especially for those who have family history of colorectal cancer or are over 40 years old. Why is it possible to know whether you are likely to have colorectal cancer by observing your bowel movement in time? After food enters the body, it is digested by the stomach, absorbed in the small intestine, and finally the food residue forms feces and is discharged through the colon and rectum, which is the complete process of converting food into energy to be absorbed by the body and then maintaining the physiological activities of the body. Thus, once a tumor grows in the lining of the colon or rectum, it will affect the feces that must be excreted through the intestine and change its texture and shape. In addition, the surface of tumor is completely different from the normal intestinal mucosa surface, so normal defecation will not cause the breakage of intestinal mucosa and blood in stool, but if the stool rubs against the surface of tumor, it will bleed easily. Once this “dangerous symptom” is detected during defecation, patients should go to regular hospitals for further examination, such as fecal occult blood test and colonoscopy, in order to make a clear diagnosis as early as possible and avoid delaying the treatment time. In addition, because almost all anorectal tumors, when bleeding occurs, the stool examination will not show simple bloody stool, but most patients’ stool will generally be mixed with pus cells and mucus, so when pus and blood stool and mucus stool appear during defecation, it also needs to attract the high attention of patients and doctors. Since hemorrhoids and colorectal cancer are similar in location and both have bloody stools, it is especially important to distinguish between bleeding hemorrhoids and colorectal cancer. Generally, blood in the stool of hemorrhoid patients is caused by bruising the affected area during defecation, and most of the blood drips down with the discharge of stool. In contrast, the stool of colon cancer patients is mixed with blood, mucus and thick liquid, and advanced colon cancer patients not only have pus and blood stools, but also have a strong foul odor, which can be separated from hemorrhoid patients. Therefore, people who have suffered from hemorrhoids for many years and often have blood in their stools should pay more attention to the screening of colon cancer, pay attention to the changes of their health conditions and go to the hospital in time once they find abnormalities, so as not to let the small hemorrhoids cover up the fact of colon cancer. In terms of prevention, good dietary habits and personal habits can effectively prevent the occurrence of colorectal cancer, so we should pay attention to adjusting dietary habits, regular work and rest, strengthening physical exercise, and adjusting psychological state to achieve physical and mental well-being and balance. In addition, people with family history of colorectal cancer, long-term blood in stool and other high-risk factors should undergo regular medical checkups, especially to detect lesions at an early stage, treat them early and minimize the occurrence of adverse outcomes.