Black Stool: Causes, Symptoms & When to See a Doctor

Colon cancer, also known as colorectal cancer, is a cancer that occurs in the large intestines. According to the Mayo Clinic, colon cancer often starts out with benign cancer cells that turn malignant over time.

Symptoms

• One of the symptoms of colon cancer is blood in the stool. The blood can either be bright or dark red. When it is dark red, it turns the stool a black tar-like color.

Time Frame

• Medicinenet.com says colon cancer can be developing for years before it is detected. The right side of the large intestine has a spacious storage area that can allow a tumor to grow to the size of a baseball before it is detected.

Significance

• Black or bloody stool is often an early symptom of colon cancer, and the North Shore Medical Center encourages people who experience blood in the stool to get to a doctor immediately.

Color Coded

• Bright red blood in the stool can be a sign of tumors in the left side of the large intestine, and black stool normally indicates a tumor growth in the right side of the colon.

Prognosis

• According to the North Shore Medical Center, if colon cancer is caught early enough, successful treatment is possible.