Yakult is a Japanese probiotic drink that has been popular for over 80 years. It is made from a special strain of lactic acid bacteria called Lactobacillus casei Shirota, which is believed to help maintain a healthy digestive system.
From Wikipedia
Yakult is a Japanese sweetened probiotic milk beverage fermented with the bacteria strain Lacticaseibacillus casei Shirota. It is sold by Yakult Honsha based in Tokyo. The name "Yakult" was coined from jahurto, an Esperanto word meaning "yogurt".