Clinically, it leads to yellow water coming out of the anus without pain, commonly in the following three cases: a. Anal fistula, especially internal anal fistula, because anal fistula is due to inflammatory infection, resulting in the formation of pus cavity around the anus, the pus cavity breaks down by itself or after surgical incision, there is the source of infection is not removed, so after inflammation occurs, purulent secretions will flow down the fistula, especially internal anal fistula from the inner mouth, some pus itself is yellow, some The pus is white and turns yellow through the rectum mixed with stool. Second, after perianal surgery, some perianal lesions after surgery, the anal sphincter is damaged, contraction ability becomes poor, control of stool is not ideal, sometimes thin stool will flow directly from the intestine, mixed with some secretions lead to the emergence of yellow water. Third, intestinal tumors, intestinal tumors will also have the performance of discharging yellow secretions, the clinical need for systematic examination and clear diagnosis in order to treat the symptoms.