Colorectal cancer may be caused by dyspepsia, local infiltration of tumor and metastasis. 1. Dyspepsia: Usually, patients with left half colon cancer will often have digestive symptoms such as abdominal pain, diarrhea, abdominal distension, etc., while patients with right half colon cancer may also have nausea, vomiting, loss of appetite, etc. If patients usually have poor dietary habits, they may be induced to eat oily and spicy stimulating food. If patients have poor dietary habits and often consume greasy and spicy stimulating food, indigestion may be induced, which may lead to intestinal tinnitus as soon as patients lie down. 2. Local infiltration of tumor: if colon cancer invades into small intestine and forms internal fistula, symptoms such as postprandial diarrhea, discharge of incompletely digested food and so on will often appear, and some patients may also show tinnitus when they lie down. 3. Tumor metastasis: if the planted metastatic foci infiltrate or press to the intestinal tube, intestinal obstruction can be induced, and the patient will have abdominal pain, abdominal distension, stopping of anal excretion, etc. Strong intestinal peristalsis will also occur in the area above the obstruction, and thus intestinal tinnitus will also occur when the patient is lying down. It is suggested that colon cancer patients should consult doctor in time and find out the cause of the disease after reasonable treatment when the symptoms of tinnitus occur, so as to avoid delaying the condition.