Stomach is the organ where majority of digestion of food particles takes place. It is most commonly affected by ulcer, gastritis, polyps & cancer.
Small intestine also called small bowel is the longest part of digestive tract. Majority of absorption of the nutrients takes place in the small intestine. It can be affected by ulcers, crohn's disease, TB & tumours. A gastro specialist or
Large intestine also called colon or large bowel is the part involved in absorption of water & electrolytes. It can be affected by colitis, diverticulitis & tumours. The doctor gastrology may suggest a colonoscopy for diagnosis of the illnesses.