The study on 37 duodenal ulcer patiens with Helicobacter pyloriinfected were treated by EAC therapy in 10 days. The results: The healing rate and eradication rate in patiens with Helicobacter pylori sensitive to Clarithromycin were higher than that in patiens Helicobacter pylori resistance to Clarithromycin (86,4 percent versus 53,3 percent, p 0,05 and 90,9 percent versus 40,0 percent, p 0,05, respectively). Helicobacter pylori resistance to Clarithromycin reduced the efficacy of treatment duodenal ulcer by EAC therapy.