AIM: To investigate the effect of Helicobacter pylori eradication on endothelin-1 (ET-1) and nitric oxide (NO) in duodenal ulcer (DU) patients. METHODS: Sixty-six Hpylori-infected active DU patients were consecutively enrolled to receive one-week triple therapy (rabeprazole, amoxicillin and metronidazole) and then one-month rabeprazole therapy. They were asked back to determine ulcer and Hpylori status using endoscopy one month later. Thirty-seven healthy controls (H pylori +/-:17/20) were enrolled for comparison. Blood samples were collected in each visit to measure plasma ET-1 and nitrate/nitrite levels using an enzyme immunoassay kit. RESULTS: Sixty DU patients finished trial per protocol. The ulcer healing and Hpylori-eradication rates were 86.7% and 83.3%, respectively. Plasma ET-1 level in DU patients was higher than that of Hpylori-negative and positive controls (3.59±0.96 vs0.89±0.54 vs0.3±0.2 pg/mL,P<0.01), while nitrate/nitrite levels among them were also significantly different (8.55±0.71 vs5.27±0.68 vs 6.39±0.92 μmol/L, P<0.05). H pylori eradication diminished ET-1 levels (3.64±0.55 vs2.64±0.55 pg/mL, P<0.01) but elevated nitrate/ nitrite level (8.16±0.84 vs11.41±1.42 umol/L,P<0.05). CONCLUSION: Both plasma ET-1 and nitrate/nitrite levels increase in active DU patients. After an effective H pylori eradication, DU healing is associated with diminished blood ET-1 level and elevated nitrate/nitrite level. AIM: To investigate the effect of Helicobacter pylori eradication on endothelin-1 (ET-1) and nitric oxide (NO) in duodenal ulcer (DU) patients. METHODS: Sixty-six Hpylori-infected active DU patients were consecutively enrolled to receive one -week triple therapy (rabeprazole, amoxicillin and metronidazole) and then one-month rabeprazole therapy. They were asked back to determine ulcer and Hpylori status using endoscopy one month later. Thirty-seven healthy controls (H pylori +/-: 17/20 RESULTS: Six samples were collected in each visit to measure plasma ET-1 and nitrate / nitrite levels using an enzyme immunoassay kit. RESULTS: Sixty DU patients finished trial per protocol. The ulcer healing and Hpylori-eradication rates were 86.7 % and 83.3%, respectively. Plasma ET-1 level in DU patients was higher than that of Hpylori-negative and positive controls (3.59 ± 0.96 vs 0.89 ± 0.54 vs. 0.3 ± 0.2 pg / mL, P <0.01), while nitrate / nitrite levels among them were also significantly dif ferent (8.55 ± 0.71 vs 5.27 ± 0.68 vs 6.39 ± 0.92 μmol / L, P <0.05) .H pylori eradication diminished ET-1 levels (3.64 ± 0.55 vs 2.64 ± 0.55 pg / mL, P <0.01) nitrate / nitrite levels (8.16 ± 0.84 vs11.41 ± 1.42 umol / L, P <0.05) CONCLUSION: Both plasma ET-1 and nitrate / nitrite levels increase in active DU patients. After an effective H pylori eradication, DU healing is associated with diminished blood ET-1 level and elevated nitrate / nitrite level.