Hormonally mediated chronic refractory diarrhoeas constitute a rare but important group which often defy precise diagnosis when conventional routine diagnostic methods are used. Hormonal diarrhoea may occur in carcinoid syndrome, medullary carcinoma of the thyroid, thyrotoxicosis, gastrinoma, VIPoma, glucagonoma, somatostatinoma and systemic mastocytosis. Diagnosis of these conditions depends upon the awareness of clinicians, on clinical features and on documentations of high circulating hormones, if required, by using provocative tests. Precise localization of the tumours may be accomplished by ultrasonography, computerised axial tomography, angiography, percutaneous transhepatic portal and pancreatic venous sampling for the estimation of hormone concentrations. Benign tumours are removed surgically. Malignant neoplasms are treated either by surgery or chemotherapy depending upon the progress of the disease. Diarrhoea usually ceases when hormone levels are normalized following successful treatment.