The anus has a hidden pain in the side of the mouth of the anus is considered to be the internal hemorrhoid embedded, anal fissure and perianal malignant tumors and other causes. 1. internal hemorrhoid embedded, the phenomenon of hidden pain in the anus, mostly considered caused by hemorrhoids, and external hemorrhoids caused by the pain is more intense, so consider the internal hemorrhoids to varying degrees of embedded, and even cause local inflammatory reaction. 2. anal fissure, anal fissure is the most typical manifestation of pain during defecation, occasional blood, but in the early stage of anal fissure, can also cause anal pain and other discomfort. 3. Perianal malignant tumors, for people with family history and high risk factors, need to consider whether perianal malignant tumors caused by anal discomfort, mostly accompanied by changes in bowel habits and traits. The phenomenon of hidden pain in the anus, it is recommended to go to the regular hospital in time, a clear diagnosis, follow the doctor’s instructions to give reasonable standardized treatment, so as not to delay the condition.