Oyakuen was used approximately 600 years ago as a villa for the then lord of the Aizu Domain. Subsequently, in the mid-17th century, the lord of the Aizu Domain started growing medicinal herbs within the grounds which he developed to protect the citizenry from epidemics. This lead to the garden gaining the name "Oyakuen", which literally means "medicinal garden."
The traditional garden has been preserved as it was long ago, and Oyakuen has now been designated as an important national asset. The buildings within the grounds were used by the lord as a place of relaxation and for entertainment. Accordingly, Oyakuen still contains buildings devoted to Japanese tea. Visitors can enjoy a cup of herbal tea here even today.