In 1981, China's Ministry of Health sought bids for the construction of a production base for quality I.V. solutions. As a result, Otsuka became the first Japanese pharmaceutical company to establish a joint venture in China - China Otsuka Pharmaceutical Co., Ltd. Today, Otsuka (China) Investment Co., Ltd., which oversees Otsuka's pharmaceutical business in China, is making effective use of human resources and technologies, while making investments in various areas in order to maximize synergies among the group companies there.
After 1981, Otsuka expanded into other areas including South Korea, Hong Kong, the Philippines, Vietnam, and Singapore. Currently, Korea OIAA, Co., Ltd., located in Seoul, is in charge of marketing and application development for Asia and the Middle East. It considers the healthcare systems across these regions, along with the business environments for products, and then establishes and promotes sales strategies specific to each market. Korea OIAA also works to increase the added value of Otsuka products. In 2014, Otsuka Australia Pharmaceutical Pty Ltd. was established as Otsuka's first pharmaceutical sales company covering the Oceania region.