Di Long or Dilong extract (Chinese: 地龍散; pinyin: dìlóngsàn; Wade–Giles: ti-lung san; lit.
The abdomen of an earthworm of the L. rubellus species is cut open immediately after capture, whereupon viscera and extraneous matter are removed.
It is also used in the treatment of blepharoptosis, or drooping of the upper eyelid, along with other Phlegm Herbs (such as Dan Nan Xing, Jiang Can, Ban Xia, Tian Ma and Bai Fu Zi).
According to TCM, Di Long is associated with the Bladder, Liver, Lung and Spleen meridians, and has Salty and Cold properties.
Its "channel-opening" properties are thought to derive from its habits of burrowing through the earth, constantly searching out new spaces to slither.