Diseases of the sigmoid colon include colitis as well as malignant tumors of the colon. For simple inflammation, anti-inflammatory treatment options are available. During acute attacks, symptoms can be gradually improved by intravenous fluid supplementation, application of broad-spectrum antimicrobial agents, or immunosuppressive agents such as azathioprine. In the case of malignant tumors of the sigmoid colon, i.e. colon cancer, the patient will experience pain and blood in the stool, as well as anemia, and in severe cases, intestinal obstruction, which can be further confirmed by colonoscopy. The most effective treatment is surgery, i.e., radical resection. Postoperative symptomatic treatment such as intravenous nutritional support and anti-infection is also required. After surgery, patients also need to choose adjuvant treatment according to detailed pathological staging, because patients with colorectal cancer usually need systemic intravenous chemotherapy after surgery.