How to Identify Blood in the Stool

Blood appears in the stool for various reasons, including infection, cancer, digestive disorders and open wounds, such as hemorrhoids and ulcers. Blood may be visible to the human eye in some cases, suggesting the blood is from the lower digestive tract. Or the blood will be less obvious, indicating it is coming from the upper digestive tract. At home, people can identify blood by examining the feces or by using a home-use fecal occult blood test available at pharmacies 1. This type of test helps identify blood that isn’t visible to the human eye.

Examine the stool carefully. If what appears to be bright red blood on a tissue after wiping, or if toilet water contains blood, the cause probably is an open wound or other form of bleeding in the lower digestive tract, according to the National Digestive Diseases Information Clearinghouse. An anal fissure or hemorrhoid can cause this type of blood. A fissure is a type of cut in the lower digestive tract. Like any other cut on the body, it can bleed. Even a small cut in the digestive tract can bleed profusely.

Look for dark-colored stool. Black stool, or stool with red blood mixed in, suggests upper digestive tract bleeding, the National Digestive Diseases Information Clearinghouse says. Report this condition to a health care provider. Some foods, like blueberries or black licorice, can cause feces to take on a dark appearance that may be resemble the color of blood.

Purchase a fecal occult blood test from a pharmacy 1. Your health care provider might provide one.

Open the package and review the instructions. Depending on the type of kit, it will contain either a flushable pad or a piece of material that resembles thick tissue paper.

Cleanse the genital and anal regions with an alcohol swab, or follow the test kit instructions for cleaning the area.

Place the tissue or flushable card into the toilet. Empty the bowels onto the materials.

Examine the flushable card for a change of color. Typically, no change after five minutes indicates no blood is present. Withdraw the tissue paper with stool sample, and touch the stool with a tester card that comes in the kit. Like the flushable card, this tester card will change color within five minutes if blood is present. Repeat the test once per day for three days or as directed by the test kit, the Cleveland Clinic says 1.

Report the findings of visual and fecal occult testing to a medical professional. He should evaluate any indication of blood to ensure the cause is not serious.


Note all other symptoms that accompany the blood in the stool, and report them to a health care professional.

Antidiarrheal medications, especially those containing bismuth salicylate, can cause darkening of the stool.


Even if the visual and fecal occult tests reveal no blood in the stool, report any unusual bowel problems to a medical care provider.

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