Introduction: Yakult is a Japanese brand. Transliteration is Yakult and Yakult, and their names are taken from the esperanto "Jahurto", which means yogurt. It is a milk beverage containing at least 1000 billion special active lactic acid bacteria per bottle. Yakult is the largest producer of lactic acid bacteria fermentation products in Japan. "Lactobacillus casei Daitian strain" was first discovered and obtained by Japanese medical doctor Ren 1930. He successfully isolated and intensively cultivated lactic acid bacteria while studying digestive lactic acid bacteria. And named it Lactobacillus casei Daitian strain. It is characterized in that the "Lactobacillus casei substitute strain" after intensive culture has the digestive juice function of resisting the strong bactericidal action of gastric juice, bile and the like, and reaches the human intestine in an active state. Its function is to reach the small intestine alive, increase beneficial bacteria and reduce harmful bacteria; Reduce harmful substances in the intestine and prevent intestinal corruption; Prevent the infection of food poisoning bacteria; Improve intestinal activity and adjust intestinal ecological balance; Improve constipation and diarrhea symptoms; Promote metabolism and health.