How is bright red not painful after defecation to return a responsibility

Bright red blood outflow after defecation but no pain may be caused by hemorrhoids, anal fissure, anal fistula and other diseases, may also be caused by malignant tumors of the digestive tract, such as colon cancer. It is recommended to identify by anal endoscopy, enteroscopy, pathology, stool routine, etc. The recent diet should be light and defecate on time.