The gastrointestinal system comprises the body organs that
perform digestion,absorption and excretion.These organs include
the mouth,pharynx,esophagus,stomach,small intestine,large
intestine and anus as well as the salivary glands,liver and
pancreas. Commonly occurring gastrointestinal diseases can be
divided into 3 categories:first,dental and oral diseases;second,
diseases of digestion and absorption,such as peptic ulcers and
colorectal carcinomas;and finally,excretory tract diseases,
namely, hemorrhoids and anal fissures