Diarrhea after gastric cancer surgery is related to indigestion and intestinal dysfunction. Gastric cancer is a malignant tumor disease, which is mainly treated by surgery, and some patients need to have all their stomachs removed. After the stomach is removed, the secretion of digestive juices will be insufficient, so it is difficult to digest the ingested food completely. Since the food is not decomposed and digested, it can cause irritation in the intestine, which can lead to diarrhea. After surgery, some people may damage the function of the intestine and even cause intestinal dysfunction, which not only affects the absorption of nutrients in the intestine, but also causes hyperactive peristalsis, thus causing diarrhea. After gastric cancer surgery, one should pay attention to good dietary care and try to focus on easily digestible and easily absorbed food, so as to reduce the occurrence of diarrhea.