My wife has rectal bleeding that comes and goes. she went to a nurse practitioner and found no hemmorhoids. what could cause this?

Go see GI: If there is no evidence of hemorrhoids...It is time to go see GI and let them take a look. She may need to be scoped to look for sources of the bleeding. More than likely it is benign, but it is worth getting it checked to know for sure.

Depends: There are multiple causes of rectal bleeding with the most common being hemorrhoids. Other causes can include colon polyps and colon tumors. Confirming that the blood is from the rectum (and not vagina), i would definitely recommend consideration for referral for colonoscopy for further evaluation. Rectal bleeding at any age should be fully evaluated.

Several things: Hard stools may cause intermittent rectal bleeding from a split in the anus, a fissure. Intermittent bleeding, however, may be a sign of inflammatory bowel disease or colon or rectal cancer. These would be serious. Have another visit and ask for a consideration of other things.