<unk> s are not usually associated with symptoms. When they occur, symptoms include bloody stools; changes in frequency or consistency of stools (such as a week or more of constipation or diarrhoea); and fatigue arising from blood loss. Anemia arising from iron deficiency can also present due to chronic blood loss, even in the absence of bloody stools. Another symptom may be an increased mucus production especially those involving villous adenomas. Copious production of mucous causes loss of potassium that can occasionally result in symptomatic hypokalemia. Occasionally, if a<unk>  is big enough to cause a bowel obstruction, there may be nausea, vomiting and severe constipation.
Colorectal polyp
Colorectal adenoma
Anal dysplasia
Anorectal varices
Gastric varices
Anal fistula
Callous ulcer
Reactive gastropathy