Otsuka Group started in 1921. Busaburo Otsuka established a chemical compound factory in Naruto, Tokushima Prefecture, now Otsuka Pharmaceutical Factory Inc. In 1946, this small-scale manufacturer of chemical raw materials began producing and selling intravenous solutions.

In 1950, the organic chemical solutions division split from Otsuka Pharmaceutical Factory to form Otsuka Chemical and Medical Products, Inc., now called Otsuka Chemical.

This was followed by the establishment of Taiho Pharmaceutical in 1963 and Otsuka Pharmaceutical in 1964. These new entities were steps in the evolution of a manufcaturer specializing in R&D.

Thai Otsuka Pharmaceutical Co., Ltd. was officially established on December 7, 1973, making it the first joint venture of the Otsuka Group to be out of Japan.

For over 40 years until today, Thai Otsuka Pharmaceutical Co., Ltd. has still adheared to the first concept when it was established for the better health of Thai people.