Patterns of dyspepsia in patients with no clinical evidence of organic diseases. We studied 2000 dyspeptic patients with no obvious signs of organic disease at their first examination, in order to (1) verify how many diagnoses of idiopathic dyspepsia had really been made after exhaustive diagnostic procedures and (2) evaluate the diagnostic power of the symptoms in distinguishing organic from idiopathic dyspepsia. This latter was considered only when no structural abnormalities were found. In all the other cases, a distinction was made between "related" and "associated" organic dyspepsia according to whether or not there was a certain relationship between the abnormalities and the dyspeptic symptoms. The patients were referred to us as follows: (1) spontaneously, (2) sent by physicians collaborating with us, (3) referred to our open access endoscopic service. The results show the frequency of idiopathic dyspepsia was 26%, whereas associated structural abnormalities were present in 45.4%. Obvious organic causes of dyspepsia were seen in 28.6% (24% benign and 4.6% malignant diseases). When considered separately, no symptom alone allows a correct diagnosis. The simultaneous evaluation of the symptoms with linear discriminant analysis distinguishes between idiopathic and organic dyspeptic patients in about 70% of the cases. A higher discrimination percentage in about 70% of the cases. A higher discrimination percentage could probably be obtained using a wider range of clinical parameters and/or a more complex statistical analysis of the interrelationships which exist between the clinical symptoms and the final diagnosis. 