Helicobacter pylori (Hp) infection is one of the important causes of gastrointestinal diseases, including gastritis, peptic ulcer, and malignancies, nd the eradication of Hp can effectively cure or prevent these diseases. Now, owing to the increasingly serious antibiotic resistance, Hp eradication rate is, however, becoming decreased. In order to improve the eradication rate of Hp, clinicians pay great attention to choose more effective treatment.

Ilaprazole Enteric-Coated Tablets is a new generation of proton pump inhibitor (PPI). Previous research found that Ilaprazole had a more prolonged half-life and higher suppression of gastric acid secretion. In addition, its metabolism is not significantly influenced by CYP2C19, compared to the available PPIs. Doxycycline is in the tetracycline antibiotic class, has a stronger antibacterial force than tetracycline and its antibacterial spectrum is basically the same as tetracycline and doxycycline, so far, it is not widely used. Preliminary observations showed that Ilaprazole/Doxycycline-based quadruple therapy was effective in treating Hp infection, with less adverse reactions and good compliance with patients.

In this study, a multi-center, randomized, parallel controlled trial will be conducted in 7 hospitals in Hunan Province, China, to observe the clinical efficacy and safety of the Bismuth-containing quadruple therapy with Ilaprazole, Doxycycline, Furazolidone and Bismuth Potassium Citrate in the treatment of Hp infected duodenal ulcer. It is expected to complete 200 effective cases, including 100 cases in the experimental group and 100 cases in the control group.

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.