Colorectal cancer clinically falls under the category of colon cancer, and many early cases of colon cancer do not have obvious symptoms.

Some patients in the early stages may experience abdominal bloating and discomfort or a sense of dull pain. This pain is generally mild and occurs intermittently, sometimes more frequently at night. Some patients exhibit repeated constipation or repeated diarrhea, a feeling of incomplete bowel evacuation, and the presence of blood in the stool or the passage of mucoid pus and blood in the stool. Other patients may experience mild belching, nausea, vomiting, and other signs of indigestion. The symptoms of early-stage colon cancer are not typical, and many patients only seek medical attention when they experience more severe symptoms such as abdominal pain, bloating, nausea, and vomiting.