Chemotherapy refers to chemical treatment, chemotherapy diarrhea is mainly the use of chemotherapy drugs appear toxic side effects, but may also be related to the body’s immunity or the patient’s mood and other factors. Chemotherapy drugs belong to the cytotoxic drugs, in the use of such drugs during the treatment, the body will have some toxic side effects, the more common is diarrhea, nausea and vomiting and other digestive system adverse reactions. But it may also be due to frequent chemotherapy led to the body’s immune system becomes low, if life is not pay attention to good care, the intestinal tract is susceptible to infection, which may also lead to diarrhea. In addition, some patients will have some negative emotions during chemotherapy, such as anxiety and fear, etc., the long-term existence of these emotions will stimulate the secretion of digestive juices, digestive fluid secretion increases, intestinal peristalsis will be affected, triggering diarrhea. It is recommended to consult a doctor for further diagnosis and treatment.