This was a randomized, double-blind, single-center, placebo-controlled, three-arm study.

The objectives of this study were to evaluate the effect of the Bright Changyou Probiotic Flavored Yogurt on:

Improving gastrointestinal health; Relieving symptoms of functional constipation or functional diarrhea; Improving gut immunity; Adjusting microbiological flora in gastrointestinal tract.

Inclusion Criteria:

• Men or women aged 25-45 years old;
• Functional constipation or diarrhea diagnosed by Rome III criteria;
• Agree not to take any dietary supplements or dairy products other than the study products during the study period;
• Agree not to take any supplements or dairy products containing prebiotics/probiotics other than the study products during the study period;
• Agree not to participant in other interventional studies during the study period;
• Fully understand the property, purpose, benefits and potential risk and side effect from the study;
• Agree to follow all study requirements and procedures;
• Signed informed consent.

Exclusion Criteria:

• Currently receiving treatment for gastrointestinal symptoms;
• Lactose intolerance;
• Having diseases or conditions that may affect intestinal function, such as history of gastrointestinal resection, colon or rectal cancer, inflammatory bowel disease, diabetes, hyperthyroidism or hypothyroidism, Hirschsprung's disease, scleroderma, or Anorexia nervosa;
• Currently under diet control or in use of medicine or supplements for weight control or that might affect appetite;
• Have had laxatives or other substance that will enhance digestion within two weeks before the study begins;
• Have had dairy products or other food containing probiotics within 10 days before the study begins;
• Currently having diarrhea;
• Currently pregnant or breast-feeding, or plan to be pregnant during the study period;
• Not be able to follow study procedures according to investigators evaluation.

Participant eligibility is based on self-representation of gender identity.