Sigmoid polyp 0.5cm is not a big size, but it is not possible to judge whether it is serious or not. It needs to be judged and treated accordingly according to the pathological findings and accompanying symptoms. 1. Adenomatous: sigmoid polyps, mostly occurring in adults, if adenomatous polyps, such as cancer has occurred, more serious. Some statistics show that if the diameter is larger than 2cm, about half of the polyps will become cancerous. If it is chorionic adenoma, the cancer rate is even higher. 0.5cm polyp is also serious, alert to the possibility of cancer, and should be timely surgical resection. 2. Inflammatory: Inflammatory polyp 0.5cm is not big. It is mostly caused by inflammatory reaction to stimulate the intestinal epithelium. It can be secondary to any kind of inflammatory reaction or infectious diseases, such as amebic colitis, chronic schistosomiasis, dysentery and so on. Generally there is no malignant tendency, but need to actively treat the primary disease. 3. proliferative: proliferative polyps are the most common non-tumor polyps in the colorectum, 0.5cm is relatively large, generally polyps <0.5cm. hairy, generally do not need treatment, but can not be identified from the appearance of tumor polyps, often endoscopic excision biopsy. If intestinal obstruction occurs, accompanied by nausea, vomiting. Endoscopic minimally invasive surgical resection is required. If colon polyps are present, medical treatment is needed to avoid delay.