Minoru Shirota, the founder of Yakult and a doctor of medicine, began his medical studies at Kyoto Imperial University (now Kyoto University) in 1921. Around that time, Japan was still not prosperous, and so unsanitary conditions caused many children to die of infectious diseases.
Disturbed by this reality, Dr. Shirota aspired to advance preventive medicine, which aims to help people avoid sickness, and started down the path of micro-organism research. In his research, he discovered that lactic acid bacteria suppress harmful bacteria in the intestines, and he succeeded in strengthening and culturing a strain of lactic acid bacteria for the first time in the world. This strain is now known as Lactobacillus casei strain Shirota.
Dr. Shirota then developed an inexpensive, good-tasting beverage, together with volunteers, so that as many people as possible could benefit from this lactobacillus, and released it under the trademark Yakult in 1935.
This was the beginning of the history of Yakult, which is now popular around the world.