Colon Polyps (cont.)

Ninety-five percent of colon polyps do not cause any symptoms or signs. The most common symptoms or signs when they do occur are those of bleeding from the polyp. This usually results in small amounts of blood in the stool, enough to turn stool tests for occult (hidden) blood abnormal, but not enough to change the color of stool. Occasionally when bleeding is substantial, the stool may become black, maroon or bright red.

More commonly, however, the bleeding continues at a slow pace and can result in anemia due to a loss and subsequent deficiency of iron. If this happens, symptoms of anemia - weakness, light-headedness or fainting especially upon standing, pale skin, rapid heart rate, and occasionally congestive heart failure, stroke, or heart attack - may occur.

(The reason that colon cancer screening often involves stool tests for occult blood is that colon polyps have a tendency to bleed; screening for blood in the stool identifies patients with a higher likelihood of having colon polyps who need colonoscopy to look for and remove the polyps.)

Source: MedicineNet.com
http://www.medicinenet.com/colon_polyps/article.htm