What are the most common causes of anal bleeding in young women?

Anon,

You are right, there can be quite a few causes. The most common is probably hemorrhoids, which can cause bright red blood in the stool and can be alarming if you don't know what's going on.

Kgroup is right -- are you straining to go to the bathroom?

Or is it possible that you have suffered a small tear during anal sex?

Generally, the color of blood signifies how close the bleeding is to the rectum. Medicinenet.com tells us that bleeding from the anus, rectum, and the sigmoid colon tend to be bright red, whereas bleeding from the transverse colon and the right colon (transverse and right colon are several feet away from the anus) tend to be dark red or maroon colored. And if it's darker brown or even black, it may be from the stomach, for instance, because it's been in the digestive tract longer.

This page discusses rectal bleeding and its possible causes in a straightforward way, and deals with everything from hemorhhoids to polyps to anal fissures:

http://www.medicinenet.com/rectal_bleeding/symptoms.htm

I'm glad you're making a doctor's appointment to get checked out. Is the above info of help?

I have also had blood in my stool and was concerned. I realized that everytime I strained on the toilet is when I'd bleed. They say you shouldn't stay on the toilet too long and not to force anything out. Try to remember when you bleed and if you had an easy bowel movement or if you had trouble.