Fructus Aurantii generally refers to the scientific name of citrulline. It is a small tree of Rutaceae and Citrus with dense branches and thorns. Leaves dark green, thick, obovate wings and narrow base. Racemes have few flowers, and the buds are oval or subglobose.

The fruit is round or oblate, the peel is slightly thick and extremely thick, which is difficult to peel, orange-yellow to vermilion, verified or semi-full, the flesh is sour, sometimes bitter or has a special smell, and the seeds are numerous and large.