There are many clinical methods to determine whether one is suffering from intestinal cancer, as follows: 1. Self-judgment: one can judge by oneself according to the symptoms, and the more typical one is mucus-purulent-blood stool. In addition, there may be painful symptoms in the abdomen; 2. Auxiliary examination: you can also rely on blood sampling and imaging examination, for example, if the carcinoembryonic antigen reaches hundreds or thousands, you must pay attention to it. Clinically, CT or MRI of abdomen can make a better judgment on the location and size of tumor as well as whether the surrounding lesions and lymph nodes are metastatic; 3. Pathological biopsy: the diagnosis of intestinal cancer ultimately depends on gastroscopic biopsy to obtain pathology, and immunohistochemistry and genetic testing if necessary, in order to make a clear diagnosis.