The Efficacy and Safety of Ilaprazole/Doxycycline-based Bismuth-containing Quadruple Therapy on Hp Infected Duodenal Ulcers

Inclusion Criteria: 1. Has endoscopic evidence of active duodenal ulcer(within a week before participate), accompanying or not accompanied with abdominal pain/abdominal discomfort, acid, heartburn, abdominal distention, belching and other corresponding symptoms. 2. The diameter of the ulcer is 0.3 to 2.0cm, and the number is less than or equal 2. 3. Has evidence(s) of Hp infection. (13C-UBT/14C-UBT/Pathological test) 4. Has a history of antiacid medication, but has been stopped for more than 2 weeks. 5. Has not used antibiotics and (or) bismuth agents in nearly four weeks. 6. Understand and be willing to participate in this clinical trial. Exclusion Criteria: 1. Has been taking ulcer medications, such as non-steroidal anti-inflammatory drugs, adrenal corticosteroids etc. 2. Has allergic and idiosyncratic responses to the tested drugs and (or) control drugs. 3. Has a diagnosis of duodenal carcinelcosis or a duodenal ulcer can not rule out the the possibility of malignancy (patients with gastrointestinal mucosal epithelial mild atypical hyperplasia are not ruled out) or compound ulcers. 4. Has severe or progressive dysphagia, weight loss, gastrointestinal bleeding or other alarm symptoms. 5. Has esophageal or gastric varices, Zollinger-Ellison syndrome, or serious complications such as pyloric obstruction, active bleeding in the endoscope; esophageal erosion or ulcers, other digestive serious diseases, Such as Crohn's disease, ulcerative colitis. 6. Has a history of gastric acid suppression surgery, esophageal surgery, or digestive organ surgery, with the exception of simple suture of perforation. 7. Is pregnant, breastfeeding or has a family planning during whole trail. 8. Has serious cardiovascular, pulmonary, hepatic, renal, hematological or endocrine disease with uncontrolled condition. 9. Has participated in other clinical trials within 3 months prior to the trial. 10. Is required to use the prescribed anti-ulcer drug during the trial. 11. Has a history of drug and (or) alcohol abuse. 12. Has restriction on sodium, with metabolic alkalosis and (or) hypocalcemia. 13. Has a long-term use of clopidogrel. 14. Has other reasons for not to participating in clinical trials.