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What would cause blood to appear occasionally during bowel movements?

Answer:
Bloody stools can suggest a number of possible conditions. Some are completely benign, others are more serious. Some possibilities include haemorrhoids, fissures, diverticulosis, ulcers, esophageal varices, inflammatory bowel disease, cancer, among others. Only a physician can properly sort out which is the actual cause.

In children, these symptoms do not usually suggest a serious health problem however you should always see your paediatrician.

If you are experiencing or have experienced bloody stools, please see a physician soon.

Please see the related links for further information.

There is a general rule that doctors go by and that is if the blood is fresh (Red) then it is harmless, usually caused by a fissure (small tear on the anus opening) or a ruptured haemorrhoid or a tear on the lining of the bowel wall.
If it is black then go to the hospital at once.
First answer by ADR0760. Last edit by Brizo0903. Contributor trust: 5 [recommend contributor recommended]. Question popularity: 180 [recommend question].