While on a business trip in Mexico, an Otsuka researcher was hospitalized with diarrhea, and subsequently suffered from dehydration. The local physician instructed him to rehydrate with carbonated soft drinks, leading him to wonder if there wasn't a more suitable beverage to quickly replenish the body's supply of ion-producing electrolytes and water. Also, he noticed that doctors would drink intravenous solution to refresh themselves after finishing surgery. This became the inspiration behind the idea to develop a "drinkable IV", a beverage close to the composition of the body's natural fluids that would easily replace lost electrolytes and water. Japan in the late 1970s was experiencing an economic boom, leading to a growing interest in health, sports and outdoor leisure activities amongst the general public. On seeing people exercising and perspiring more, Otsuka set their target on developing a healthy beverage that could be easily consumed as a part of daily life. Thus, in 1980, POCARI SWEAT was launched.

While there was a growing interest in healthy living, consumers had neither seen nor tasted a product like this before, and initially they rejected it out of hand. Seeing this, the POCARI SWEAT team researched everyday conditions in which people sweat and sought to convey the concept behind the product, and the importance of replacing lost electrolytes and water. Staff handed out sample bottles at saunas, baseball stadiums, and other places where people were sweating from heat and exercise, in addition to handing out samples to shoppers. In total, 30 million bottles were distributed in 1980, and after a sustained effort, customers at sports facilities responded well by championing the product. POCARI SWEAT was pitched as a form of drinkable sweat replacement that provided the body with exactly what it needed, and when needed. The product gradually gained traction and then, two years after its debut, became a big hit. This marked Otsuka's successful development of an entirely new market for electrolyte-replacement drinks. This was also a challenge to common sense, which at the time considered hydration during sports as taboo. POCARI SWEAT demonstrated the need to supplement fluids and electrolytes, which is now taken for granted. POCARI SWEAT continues to offer unique value as a health beverage that benefits people through the expertise and unwavering concept cultivated in the medical field, educational activities, and so on.

Since introducing POCARI SWEAT, Otsuka has continued to research electrolyte and fluid replacement. The resulting data has provided additional evidence that the product may be useful in dry environments or during long-haul air travel, with its related risks of pulmonary embolism and deep vein thrombosis (economy class syndrome). In 1992, the term "heat disorders" was largely unknown in Japan. Otsuka was the first company to cooperate with the Japan Sport Association to form a research team dedicated to finding countermeasures to heat disorders associated with sporting activities. Seeking to promote a wider understanding of heat disorders, we continue to share information about the importance of electrolyte and water replenishment for safety in sports. Today still, in addition to sports we provide guidance on safe hydration in the workplace and for the elderly. Our personnel visit various locations, holding lectures and disseminating the latest information on effective hydration. In 2018, POCARI SWEAT ICE SLURRY was launched based on the expertise accumulated through earlier research into heatstroke. Conventionally, ICE SLURRY^* would have been considered difficult to commercialize from the viewpoint of production and storage. However, by developing a unique technology that freezes and partially solidifies a liquid so that it can be stored at room temperature, it maintains its jelly-like state even when refrozen. With the aim of eliminating heatstroke accidents, we have proposed a new countermeasure option for heatstroke, in the form of an entirely new "drinkable ice".

Just two years after the Japan launch, POCARI SWEAT was launched internationally. Today, it is available widely and is particularly popular in Asia. For example, in Indonesia, the product is used as a means of accessible first aid to help recuperate from fever and diarrhea. By rolling out the product to meet the needs of regional customs and cultures, it is now viewed internationally as an indispensable health drink.