How common is anemia with hemorrhoids?

Bleeding. Anemia is not uncommon. I see it in approximately 3 percent of sufferers from internal hemorrhoids. But one should also consider other causes of anemia like colon cancer in that case.
Not really. While hemorrhoids can bleed, the amount of actual blood loss is typically slight, so anemia is very uncommon with bleeding hemorrhoids. If you are on blood thinners, such as Aspirin and warfarin, the bleeding might be more impressive, but again anemia would be unexpected.
Rare. Generally, if you have anemia and hemorrhoids chances are the anemia is from something other than hemorrhoids. You would have to lose a lot of blood from a hemorrhoid to cause anemia.
Not common. If hemorrhoidal bleeding is so severe that it causes anemia, a more detailed work-up should be performed. It would be important to discuss with a doctor or hemorrhoidal specialist such as a colorectal surgeon or general surgeon in order to both create a plan to treat the hemorrhoids and to ensure that the hemorrhoids are actually the source of anemia and not bleeding elsewhere.
Not Common. Although anemia from bleeding hemorrhoids certainly does occur, it is relatively rare. A chart review study from 1976 through 1990 at the mayo clinic and olmsted community hospital in minnesota showed the incidence of this was about 1 patient out of 200, 000 population per year. Most of these patients described squirting blood or passing clots. A colonoscopy can exclude other causes of bleeding.