Rectal cancer is a common malignant tumor in the gastrointestinal tract, which is called “locked hemorrhoid” in Chinese medicine. The incidence rate of rectal cancer in China is the fourth most common tumor in the whole body, and the incidence rate of developed countries such as Europe, America and Japan is higher than that of underdeveloped countries including China. The incidence rate of rectal cancer in China has been on the rise in recent years, which is somewhat related to the rising economic level and the gradual increase of high-fat diet in China. The incidence age of rectal cancer is mostly above 40 years old, but in recent years, there is a trend of lower age. In China, rectal cancer is mostly low rectal cancer, while in Europe and America, it is mostly high rectal cancer, and in recent years, there is a trend of development of the incidence site to high. Xu Xiangtong, Department of Proctology, Xuzhou Hospital of Traditional Chinese Medicine The causes of rectal cancer are not yet clear and are mainly related to the following aspects: 1. Dietary factors: the so-called Western diet with high fat, high protein and low fiber is considered to be related to the onset of rectal cancer. It is believed that high-fat and high-protein food can increase the carcinogenic substances produced in feces; reduced fiber slows down the speed of feces passing through the intestine, which increases the contact time between carcinogenic substances and intestinal mucosa, thus increasing the incidence of rectal cancer. 2, adenoma cancer: adenomatous polyps can become cancerous, polyps are also known as precancerous lesions. 3.Inflammatory bowel disease: long-term episodes of ulcerative colitis, Crohn’s disease and other inflammatory bowel diseases can induce rectal cancer. 4.Other factors: immune function defects, genetic factors, viral infection, after gastric and gallbladder removal. When we have the following symptoms, we should be alert to the occurrence of rectal cancer: firstly, blood in stool, which is the most common symptom of rectal cancer, with red or dark red color, mucus blood stool or pus blood stool mixed in stool, sometimes accompanied by blood clots and necrotic tissue. The next symptom is the change of stool habit, such as frequent bowel movements, incomplete bowel movements, and irritation of the intestines, which is commonly called “pseudo-diarrhea”. There are also symptoms of intestinal stricture and obstruction, such as thin stool pattern, grooves, difficulty in defecation, constipation, abdominal distension and discomfort, etc. There are also anal pain and anal incontinence, which are caused by the invasion of lower rectal cancer into the anal canal and its sphincter. Advanced rectal cancer will show pain in the sacrum and perineum. Commonly used diagnostic methods: 1.rectal finger diagnosis: it is the most simple and effective method to diagnose rectal cancer; 80% of rectal cancer can be palpated through finger diagnosis, while 80% of rectal cancer is also missed because rectal finger diagnosis is not performed. 2.Proctoscopy, sigmoidoscopy and e-colonoscopy, together with pathological examination. 3.Barium enema examination, intracavitary ultrasound examination, pelvic CT examination. 4.Blood examination: mainly immunomarker examination, such as carcinoembryonic antigen, has certain diagnostic value for middle and late stage rectal cancer. The treatment principle of rectal cancer is to adopt comprehensive treatment mainly based on surgery. Its five-year survival rate is about 50%. The commonly used surgical methods are divided into anus-preserving surgery and non-anus-preserving surgery, which are applicable to high-grade and low-grade rectal cancer respectively. With the use of anastomosis, some surgeries that could not preserve the anus have been turned into anus-preserving surgeries, which greatly improved the quality of life of patients. Adjuvant treatment mainly refers to radiotherapy and chemotherapy, which can reduce 46% of pelvic recurrence and 37% of systemic recurrence, and the mortality rate can be reduced by 24%. The prevention of rectal cancer should pay attention to the following points: firstly, we should pay attention to diet, eat more light and fiber-rich food, and eat less fine food with high fat and high protein. Secondly, we should maintain a good state of mind, smooth emotions and keep good habits of life and living, do not sit or stand for a long time and do not overwork. At the same time, we should timely treat hemorrhoids, anal fistula, rectal polyps and other anal diseases, and regularly go to the hospital for specialist examination, as early rectal cancer can be cured.