Hello and welcome to Healthcaremagic.com. Women and people with chronic diseases are at increased risk of anemia. Seniors may also have a greater risk of developing anemia because of poor diet and other medical conditions. There are more than 400 types of anemia, which are divided into three groups: Anemia caused by blood loss Anemia caused by decreased or faulty red blood cell production Anemia caused by destruction of red blood cells Red blood cells can be lost through bleeding, which can occur slowly over a long period of time, and can often go undetected. This kind of chronic bleeding commonly results from the following: Gastrointestinal conditions such as ulcers, hemorrhoids, gastritis (inflammation of the stomach), and cancer Use of nonsteroidal anti-inflammatory drugs (NSAIDS) such as aspirin or ibuprofen You stated that your mother has had a colonoscopy that was negative. NSAIDs can cause gastric bleeding, but that would have been discovered during the colonoscopy. If your mother also had an EGD (which is common) at the same time, that would have investigated the upper GI tract. The body may produce too few blood cells or the blood cells may not function correctly. In either case, anemia can result. Red blood cells may be faulty or decreased due to abnormal red blood cells or the a lack of minerals and vitamins needed for red blood cells to work properly. Conditions associated with these causes of anemia include the following: Sickle cell anemia - affects African American populations Iron deficiency anemia - An iron-poor diet, especially in infants, children, teens, vegans, and vegetarians Vitamin deficiency - vitamin B-12 and folate are deficient. Bone marrow and stem cell problems Other health conditions - Bone marrow and stem cell problems may prevent the body from producing enough red blood cells Anemia associated with other conditions usually occur when there are too few hormones necessary for red blood cell production. When red blood cells are fragile and cannot withstand the routine stress of the circulatory system, they may rupture prematurely, causing hemolytic anemia. Hemolytic anemia can be present at birth or develop later. Sometimes there is no known cause (spontaneous). So, in answer to your question, yes cancer could cause anemia, but she would be complaining of other symptoms as well. Many cancers can cause anemia, but bowel cancers most commonly cause iron deficiency anemia. Once again, the colonoscopy was negative and this would have uncovered any masses in the colon. Your mother s family physician should order the tests needed to discover the type of anemia your mother has. Be well, Dr. Kimberly