['We studied the effect of Lactobacillus reuteri strain SD2112 Tablets Reuterina (ERINA Co., Inc.), in suppressing H. pylori urease activity and to use the urea breath test (UBT) as a marker for the burden of infection. Method 1: Assessment of UBT and H. pylori density. Subjects were 33 H. pylori-positive patients from whom were obtained gastric biopsy specimens by upper gastrointestinal endoscopy. The correlation between UBT and H. pylori density was investigated. Individual UBT was established for each patient. Patients were divided by H. pylori density was 3 groups: Group I (low-density), Group II (moderate-density), and Group III (high-density). The individual UBTs were then correlated to the established H. pylori quantity. Method 2: Assessment of suppressive effect of L. reuteri on H. pylori urease activity. Subjects were 40 asymptomatic volunteers with an UBT exceeding 15 per thousand, randomly allocated to four groups: Subjects in Group A underwent active treatment for 4 weeks (period 1) and placebo treatment for the following 4 weeks (period 2). These in Group B underwent treatment in reverse order. Those in Group C underwent placebo. Group D consisted of volunteers with negative UBT undergoing active treatment for the full 8 weeks. Result 1: UBT was 11.6+/-2.0 per thousand, 22.1+/-2.6 per thousand, and 35.4+/-7.6 per thousand in Groups I, II, and III, showing UBT that increased significantly (I vs. II: p< 0.01 and I vs. III: p<0.05) based on H. pylori density. Result 2:Significant differences were seen in the decrease in UBT before versus after medication in Groups A and B. In Group A, lower UBT was maintained until the end of the full 8-week period. The overall decrease in UBT due to medication with L. reuteri Tablets was 69.7+/-4.0% (p<0.05).'] Do lactobacillus reuteri tablets suppress Helicobacter pylori infection -- a double-blind randomised placebo-controlled cross-over clinical study?