1.Surgical factors Colon cancer surgery requires removal of part of the intestinal segment, which reduces the reabsorption of water in the large intestine and weakens the ability to store feces, resulting in increased water content in the stool and more frequent defecation. Some middle and low rectal cancers require preserving the anus, because the tumor is close to the anus and the position is low, the surgical field needs to be fully exposed during surgery, and the tissue pulling may damage the anal sphincter or pelvic floor nerve, resulting in postoperative anal sphincter dysfunction, which may also cause diarrhea. 2, chemotherapy and radiotherapy factors After colon cancer surgery, most of them need adjuvant chemotherapy, and some rectal cancer patients need radiotherapy after surgery to improve the cure rate and reduce recurrence and metastasis. However, chemotherapy drugs can have direct toxic effects on intestinal wall, causing necrosis of intestinal wall cells, resulting in impaired absorption and diarrhea; radiotherapy can cause radioactive enteritis and diarrhea. 3.Intestinal environment factors Colon cancer surgery can reduce the number of intestinal probiotic bacteria, and the use of antibiotics can inhibit the normal flora that are sensitive to them, making certain drug-resistant strains and harmful flora multiply, and the original balance is broken, causing intestinal flora imbalance and diarrhea. 4, dietary factors after surgery, patients are often weak, family members hope that patients can recover as soon as possible, chicken, fish, meat and eggs, needless to say, sea cucumber, abalone also idea to send, a variety of nutritional products, health products are all the time, would like to let patients eat all at once, in fact, at this time the patient’s gastrointestinal function has not fully recovered, some food can not be absorbed, some food does not have its advertised effect, eat more On the contrary, eating too much of them will increase the burden of stomach and intestines, leading to indigestion and diarrhea. After colon cancer surgery, it is recommended that: 1. Diet adjustment Generally speaking, if patients have anal discharge after surgery, they can start to eat liquid food, such as rice soup or porridge, and gradually transition to semi-liquid and general food. The diet should be light and mild, with few and many meals, avoiding spicy and stimulating foods, and avoiding foods that are too salty, too cold, too hot and produce too much gas. Especially during chemotherapy, you should not eat greasy, seafood and other hard-to-digest food, you can eat carbohydrate-rich food to increase the absorption of water and salt. 2, drug treatment Diarrhea during chemotherapy may be related to chemotherapy drugs, especially diarrhea caused by oxaliplatin is often more serious, should be given enough attention, can be given to Emmon stop or Simethicone. Diarrhea that occurs during or after radiotherapy should be considered the possibility of radiation enteritis. In addition, for patients with mild diarrhea, those who have <4 bowel movements per day may not be given antidiarrheal drugs; for those who have more than 4 but less than 10 bowel movements per day, they may be given compound phenylephrine 1 or 2 tablets/time, 2 or 3 times/day orally; for patients with moderate diarrhea, those who have more than 10 bowel movements per day, they may be given compound phenylephrine 2 tablets/time, 3 times/day orally. If the number of bowel movements is 10-20 times/day, the patient should consult a doctor promptly, give intravenous nutrition therapy, and pay attention to prevent the imbalance of water and electrolyte balance. 3, dysbiosis treatment can be done stool flora analysis or stool culture, if the proportion of cocci and bacilli in the stool is out of balance, the diagnosis is clear, the original use of antibacterial drugs should be discontinued, if necessary, according to drug sensitivity testing, the choice of appropriate antibiotics to inhibit the overgrowth of bacteria, can also be used to regulate the intestinal flora drugs such as bifidobacteria preparations. 4.Surgical treatment For radiation enteritis caused by radiotherapy, according to the severity of the disease and the patient's general condition, different surgical methods can be selected for treatment. If the rectal mucosa bleeds more than once, the mild ones can be treated with drug enemas or formaldehyde cauterization of the rectal mucosa, and the severe ones can be treated with temporary intestinal stoma or intestinal canal resection. The choice of surgical method needs to be judged by a professional doctor, and it is recommended to be treated in a public specialized hospital.