Black or Bloody Stools

Stools that look tarry, black, or bloody can be alarming, but they are not always a sign of serious illness. To understand what to do about this symptom, it is important to recognize which unusual-looking stools are simply bothersome and which require a visit to the doctor.

Causes

There are many reasons stools may be black, tarry, or bloody. The most common problems, along with the ways to treat them, are listed below.

• Foods. Large amounts of iron or iron-rich foods, such as spinach and beets, can cause stools to temporarily turn black. This change is not cause for concern. The color of the stools will return to normal after a time.

• Medications. Iron preparations and stomach medications that contain bismuth compounds can cause stools to darken or turn black. Stool color will return to normal when you stop taking the medication.

• Hemorrhoids. Swollen blood vessels in the anal canal and lower rectum are a common cause of pain, itching, and rectal bleeding, especially during bowel movements. People with hemorrhoids may notice bright red blood on the toilet tissue or on the stool itself. Hemorrhoids can be relieved through self-care steps. However, you should see your doctor if they recur or persist for more than 5 days.

• Ulcerative colitis. Frequent, mucus-covered bloody diarrhea accompanied by fever and weight loss can be caused by an intestinal disorder called ulcerative colitis. This condition is serious and must be treated by a doctor.

• Colorectal cancer. Blood in the stool can be a symptom of colorectal cancer. This form of cancer may also cause abdominal pain and changes in bowel movements. If your stools are bloody, you should see your doctor to get screened for colorectal cancer. This cancer is often curable when it is detected and treated early.

• Peptic ulcer or other gastrointestinal disease.  Heavy bleeding from upper gastrointestinal disease can present as black, tarry or bloody stool.