Clam Shell hǎi gé qiào · 海蛤壳

Meretrix meretrix Linnaeus; Cyclina sinensis Gmelin (Meretricis Concha; Cyclinae Concha)

Nature and flavour. Bitter, salty and cold; Lung and Stomach systems.

Traditionally classed as clearing Lung heat and transforming phlegm, softening hardness and dissipating masses, promoting urination, and checking acid. The drug is the shell of marine clams, used raw or calcined. Recorded for thick, hot phlegm with cough and congested breathing, for scrofula and goitre attributed to congealed phlegm-fire, and for epigastric pain with acid regurgitation. The acid-checking use is the one that survives in modern practice, and the calcined form is the one traditionally preferred for it.