Helicobacter pylori infection and NSAIDs are considered the two most important exogenous factors in ulcer disease. The interrelation between the two factors is not, however, clear. Moreover, serum pepsinogen has been suggested as a risk marker for the development of NSAID-induced gastrointestinal lesions. Fifty-one healthy volunteers, enrolled in a prospective, double-blind study carried out to evaluate gastrointestinal side effects of meloxicam and piroxicam, were analyzed to determine whether: (1) the prevalence of H. pylori correlates with the occurrence and severity of NSAID-induced gastrointestinal lesions, and (2) serum pepsinogen A and C levels could be used as markers of NSAID-induced mucosal damage. Upper endoscopy was performed by the same investigator before and after 28 days of treatment with placebo, meloxicam (7.5 mg/day and 15 mg/day), or piroxicam (20 mg/day). NSAID-induced damage was graded separately for hemorrhages and erosion ulcers according to Lanza's scale. There were no statistically significant differences in the prevalence of H. pylori in subjects with and without NSAID-induced mucosal lesions. However, there was a positive association between H. pylori infection and the severity of mucosal damage: total mean endoscopic score was 2.9 +/- 0.3 in H. pylori-positive subjects versus 1.6 +/- 0.5 in H. pylori-negative subjects (P < 0.05). Pepsinogen A and C levels increased from 55.3 +/- 3 to 149.4 +/- 15 and from 6.3 +/- 0.5 to 11.5 +/- 2.2, respectively (P < 0.05) in subjects who developed severe endoscopic injury.(ABSTRACT TRUNCATED AT 250 WORDS)