Arca Shell is the shell of Arca subcrenata Lischke, Arca granosa Linnaeus or Arca inflata Reeve (Fam. Arcidae).

Action: To eliminate phlegm, to remove blood stasis, to soften hard masses and dissolve lumps, and to relieve gastric pain by reducing acid.

Indications: Retention of sticky phlegm difficult to expectorate; goitre, scrofula, masses in the abdomen; gastric pain with acid regurgitation.