We have carried out a longitudinal study in order to confirm our preliminary data on the heavier involvement of the duodenum compared to the stomach after non aspirin non-steroidal anti-inflammatory drugs (NSAIDs). 53 patients with upper digestive haemorrhage due to recent intake of NSAIDs without preexisting known peptic pathology -28 p. from aspirin and 25 p. from NSAIDs other than aspirin--were selected. Aspirin and its derivatives mainly affected gastric mucosa whereas non aspirin NSAIDs the duodenum. 42 of these patients have been observed for two more years; independently of the treatment, ranitidine 150 mg daily vs antacids if needed, the annual rate of recurrence has been very low. These findings have further confirmed the accurate selection of our patients without previous peptic pathology (in this case the rate of recurrence would have been much higher) and also suggest a more rational diagnostic and therapeutic approach to these patients. We then observed a consecutive series of 107 patients affected with duodenal ulcer bleeding: 51 by NSAIDs and 56 not by NSAIDs; both groups were given H2-antagonists and blood transfusions if needed. The short term prognosis has been rather positive mainly for the NSAIDs group, in which no mortality has been observed, independently of the number of blood transfusions and length of hospitalization. In our experience the high percentage of NSAIDs duodenal ulcers (about 50%), shows an increase of this pathology, less severe than peptic one, even if expressed by a serious event as digestive bleeding. It is our opinion that these percentages and prognostic evaluations should be considered in therapeutic decision, limiting thus surgical and aggressive endoscopic procedures.