If there are symptoms, the following may indicate colon cancer: 1  Abdominal pain and tenderness in the lower abdomen. 2  Blood in the stool. 3  Diarrhea, constipation, or other change in bowel habits. 4  Narrow stools. 5  Weight loss with no known reason.
Diarrhea may be caused by: lactose intolerance. bacterial infection. damage to intestinal wall. hormone-producing tumors (including certain types of pancreatic neuroendocrine tumors) inflammation or ulceration of the bowel. malabsorption caused by surgery that has shortened the intestines. pancreatic enzyme insufficiency.
Bacteria and parasites. Contaminated food or water can transmit bacteria and parasites to your body. Parasites such as Giardia lamblia and cryptosporidium can cause diarrhea.Common bacterial causes of diarrhea include campylobacter, salmonella, shigella and Escherichia coli.ormally, your colon absorbs liquids from the food you eat, leaving a semisolid stool. But if the liquids from the foods you eat aren't absorbed, the result is a watery bowel movement. A number of diseases and conditions can cause diarrhea. Common causes of diarrhea include: