This is a randomized controlled trial, to evaluate the effect of WONDERLAB Probiotic Compound Powder on improving immunity of preschool children

The community hospital will recruit 140 preschool children, aged 5 to 6 years old, according to the inclusion and exclusion criteria, and randomly assigned them to 2 groups. 70 subjects in the placebo group and 70 in the experimental product group.

First entered a one-week washout period, and then entered a 25-week clinical intervention, and finally ensured that 100 volunteers completed the whole study, and the withdrawal rate was about 28%.

Inclusion Criteria:

• Preschool children, male or female, 5 to 6 years old;
• Those with weak constitution and easy to get sick:

One of them can be satisfied:

AGet cold ≥ 3 times a year B Bronchitis or pneumonia ≥2 times per year C Rotavirus diarrhea ≥1 time per year

• During the trial, participants agree not to take any drugs, supplements, or other dairy products containing probiotics;
• During the trial, participants agree not to take any other prebiotic/bacterial drugs, supplements, or dairy products including yogurt drinks;
• Willing to refrain from participating in other interventional clinical studies during the trial period;
• Be able to fully understand the nature, purpose, benefits and possible risks and side effects of the research;
• Willing to obey all test requirements and procedures;
• Informed consent signed by parents or legal guardians.

Exclusion Criteria:

• Subject who is in the treatment of gastrointestinal diseases;
• Subject who has lactose intolerance;
• The subjects are currently suffering from other organic diseases that affect intestinal function, such as history of gastrointestinal resection, colonic or rectal cancer, inflammatory bowel disease, diabetes, hyperthyroidism or hypothyroidism, Hirschsprung's disease, scleroderma, anorexia nervosa, etc.;
• Subjects have any of the following medical histories or clinically diagnosed diseases that may affect the evaluation of the test effect: obvious gastrointestinal dysfunction, liver, kidney, endocrine, blood, respiratory and cardiovascular diseases;
• According to the judgment of the researchers, frequent use of drugs that may affect gastrointestinal function or the immune system;
• Subjects who took laxatives or other digestive aids 2 weeks before the start of the study;
• Consumed dairy products or other foods containing prebiotics/bacteria within 10 days before the start of the study;
• PI believes that volunteers cannot fully cooperate with the trial arrangement.