Capecitabine is an innovative drug in the field of chemotherapy, with proven efficacy in the treatment of colorectal, breast and gastric cancers, as well as new explorations in pancreatic, prostate and kidney cancers. Capecitabine itself does not have the ability to kill, but can only be transformed into a drug with killing power after activated by TPase in the body. Because of the high TPase activity in cancer cells and the low TPase activity in normal tissues, capecitabine is activated in a large amount in cancer cells, which has great killing power to cancer cells, while it is only activated in a small amount in normal cells, which has little damage to normal cells, and the adverse effects are greatly reduced. The main adverse reactions of capecitabine are hand-foot syndrome and diarrhea, and their diagnostic criteria are as follows: Hand-foot syndrome classification criteria: Grade 1: pigmentation, numbness, itching, painless erythema and swelling of hands and feet, not affecting daily life; Grade 2: painful erythema and skin swelling of hands and feet, affecting daily life; Grade 3: skin flaking, blistering and ulceration of hands and feet with pain, unable to take care of daily life. Diarrhea grading criteria: Grade 1: 4 additional bowel movements per day; Grade 2: 4-6 additional bowel movements per day, or nocturnal stools; Grade 3: ≥7 additional bowel movements per day, or fecal incontinence, or need for parenteral supportive therapy for dehydration; Grade 4: need for intensive intensive care, or hemodynamic crisis.