The effects of various nonsteroidal antiinflammatory drugs on the gastric mucosa were endoscopically evaluated in 40 normal volunteers. Eight groups, each containing five subjects were designed: aspirin (3600 mg/d); placebo; ibuprofen (1600 mg/d); ibuprofen (2400 mg/d); indomethacin (100 mg/d); indomethacin (150 mg/d); naproxen (500 mg/d); and naproxen (750 mg/d). All volunteers took medication for seven days and gastroscopy was carried out on day one and day eight. All findings were documented by photography. Severe gastric mucosal injury occurred with aspirin (P<0.05), both="" doses="" of="" indomethacin,="" and="" the="" higher="" dose="" of="" naproxen.="" lesser="" changes="" were="" seen="" with="" the="" lower="" dose="" of="" naproxen,="" both="" doses="" of="" ibuprofen="" and="" placebo.="" the="" higher="" doses="" of="" ibuprofen,="" indomethacin,="" and="" naproxen="" caused="" a="" greater="" degree="" of="" gastric="" mucosal="" injury,="" but="" statistical="" significance="" was="" achieved="" only="" with="" naproxen=""><0.01). subjective="" gastrointestinal="" complaints="" generally="" correlated="" with="" endoscopic="" pathology;="" however,="" nine="" volunteers="" had="" evidence="" of="" severe="" injury="" to="" the="" gastric="" mucosa="" with="" no="" symptomatology.="" this="" was="" confined="" to="" the="" patients="" on="" indomethacin,="" naproxen,="" and="" ibuprofen.="" aspirin="" patients="" all="" had="" some="" degree="" of="" symptomatology="" but="" to="" a="" lesser="" degree="" than="" expected="" in="" view="" of="" the="" endoscopic="">