How digestive diseases are grouped

The digestive system is not a single organ but a chain of organs working together. This is why the same symptom, such as abdominal pain or difficulty swallowing, can arise from entirely different sites.

Upper gastrointestinal tract

Oesophagus and stomach. This includes gastro-oesophageal reflux with Barrett oesophagus, motility disorders presenting with dysphagia and chest pain, eosinophilic oesophagitis and gastritis with Helicobacter pylori.

Lower gastrointestinal tract

Small and large bowel, covering inflammatory bowel disease, coeliac disease, diverticula and constipation. Polyps hold a special place, because their timely removal is the mechanism by which colonoscopy prevents colorectal cancer rather than merely detecting it.

Liver, biliary tract and pancreas

Fatty liver disease is now the commonest liver condition and can progress through fibrosis to cirrhosis, with complications such as varices. Viral hepatitis remains an important cause, with hepatitis C now curable. In the biliary tract, stone disease dominates and is also the commonest cause of acute pancreatitis.

Gastrointestinal oncology

Colorectal cancer, gastric cancer, oesophageal cancer, pancreatic cancer, hepatocellular carcinoma, cholangiocarcinoma and neuroendocrine tumours. What they share is that early stages are silent. This is why screening and the investigation of alarm features matter more than waiting for symptoms.

Frequently asked questions

Which symptoms should not wait?

Unexplained weight loss, blood in the stool or black stools, worsening difficulty swallowing, persistent vomiting, iron deficiency anaemia, jaundice, and nocturnal symptoms that wake you from sleep. These require prompt medical assessment at any age.

When does colorectal cancer screening begin?

At 45 for people at average risk, regardless of sex. Earlier and more frequently for those with a family history of colorectal cancer or polyps, a hereditary syndrome, or inflammatory bowel disease.

Where does the investigation of symptoms start?

With history and clinical examination, which determine what investigation is needed. Because the same symptom can arise from different organs, the order of tests matters. Where alarm features are present, investigation proceeds without delay.

Content last updated: September 2026 (14/09/2026).