One month after colon cancer surgery, nausea during bowel movement may be due to unrecovered intestinal function, gastritis, postoperative intestinal obstruction and so on. 1. Bowel function has not recovered: when undergoing colon cancer surgery, the bowel will be damaged, resulting in bowel dysfunction, and some patients have a longer recovery time. When the intestinal function disorder occurs, it may lead to nausea and other symptoms, which need a certain recovery time. 2. Gastritis: Gastritis can also cause nausea, vomiting and other symptoms, and some patients also have epigastric pain, abdominal distension and loss of appetite and other discomforts. Increased abdominal pressure during bowel movements may lead to nausea and other symptoms. 3. Postoperative intestinal obstruction: one month after colon cancer surgery, postoperative intestinal obstruction may occur, causing nausea, abdominal pain, vomiting, abdominal distension and other symptoms. Patients should consult doctor for examination in time if they feel unwell after colon cancer surgery, and do not use medicine privately, which may cause harm to the body.