There's blood in the stool, but there's no blood behind it. What's going on?

Stool suddenly has blood but behind are not likely to be hemorrhoids, anal fissure, intestinal polyps and other reasons, details are as follows:

1, hemorrhoids

with hemorrhoids, varicose veins around the anus, in the forced defecation can lead to blood in the stool, if the amount of bleeding is not large, may only temporarily appear blood, and then disappear.

2, anal

fissure patients around the anus skin tear, will cause a small amount of bleeding, manifested as blood on the surface of the stool. Anal fissure pain is usually more intense, may affect defecation.

3, intestinal polyps

intestinal polyps are intestinal wall benign bulge, sometimes because of stool friction and bleeding, bleeding is usually intermittent.