Chaoshan is located in the southeast of Guangdong province, where there are many kinds of fruits in four seasons, and it is famous as the "hometown of preserved fruits", among which the most famous preserved fruits are the old medicine orange, old fragrant yellow and yellow-skinned lobster sauce, which are called "the three treasures of Chaozhou".

Chaoshan area is rich in food culture, mostly for light health preservation. The "Three Treasures of Chaozhou" is chaozhou people's concentration on healthy diet. They are all medicinal foods with high medicinal value, among which the old medicine orange is one of the best among preserved fruits.

The old medicine tangerine is pickled with local excellent kumquat as raw material and licorice, salt and honey as auxiliary materials. Kumquat itself is sour and sweet, producing saliva to quench thirst. Made by the traditional ancient decocting process, repeatedly steaming and drying for nine times, and finally storing the aged old medicine orange in a jar.