Gastroenterology is a medical sub-specialty focused on the diagnosis and treatment of diseases affecting the digestive system, including the oesophagus, stomach, intestines, liver, pancreas, and biliary tract. It involves managing conditions such as gastroesophageal reflux disease (GERD), inflammatory bowel disease (IBD), liver disorders, and gastrointestinal cancers. Gastroenterologists perform diagnostic procedures like endoscopy and colonoscopy, and often collaborate with other specialists to provide comprehensive care for complex digestive disorders.