The Efficacy of Treatment for Helicobacter Pylori Infection in Preschooler by Yoghurt With LG21

The goal of this non-randomized, open-label, interventional trial is to study the efficacy of treatment for Helicobacter Pylori Infection in Preschooler aged 4-6 by Meiji Yoghurt with LG21. The main question it aims to answer is: \- whether the treatment by Meiji Yoghurt LG21 is effective by stool antigen (HpSA) test 140 qualified participants will be enrolled and non-randomized into 2 groups of the same size (product study group and blank control group). Participants of the product study group will need to eat assigned Meiji Yoghurt for 12 weeks, one bottle each day, while participants of the blank control group won't receive any intervention during the study. Four visits will be made for all participants, and relevant clinical data will be captured and recorded into CTMS (Clinical Trial Management System) for statistical analysis and reporting.