Main Symptoms of Functional Gastrointestinal Disorders Functional gastrointestinal disorders (FGIDs) are symptom-based conditions without structural or biochemical abnormalities sufficient to explain the complaints. They involve any gut segment from esophagus to anus, often overlap, and fluctuate with diet, stress, and hormonal cycles. Recognising the dominant symptom pattern guides targeted evaluation and avoids unnecessary testing. Esophageal cluster Heartburn and regurgitation: burning retrosternal rise of acid or bitter fluid, worse after large meals or recumbency. Globus sensation: persistent lump or tightness in the throat between swallows, not during eating. Chest pain: midline squeezing or stabbing, sometimes indistinguishable from cardiac origin. Gastro-duodenal cluster... Learn more