To evaluate eradication rates of Helicobacter pylori infection in functional dyspepsia patients amongst Thai population, compare between a 10-day sequential regimen (lansoprazole 30 mg b.d. plus amoxicillin 1000 mg b.d. for 5 days then lansoprazole 30 mg b.d., metronidazole 400 mg b.d. and clarithromycin 500 mg b.d. for the remaining 5 days) with a 10-day high dose PPI-based triple regimen (lansoprazole 60 mg b.d. plus clarithromycin 500 mg b.d. and amoxycillin 1000 mg b.d. for 10 days)