One of the ten formula types. Astringent [medicinals] can eliminate desertion, i.e., they can treat efflux desertion and insecurity patterns. Formulas in which such medicinals predominate are called astringing formulas. For example, Oyster Shell Powder (牡蛎散mǔ lì sǎn), which contains oyster shell (Ostreae Concha, 牡蛎mǔ lì), ephedra root (Ephedrae Radix, 麻黄根má huáng gēn), and astragalus (Astragali Radix, 黄芪huáng qí), treats spontaneous sweating after disease due to insecurity of defense qì, whereas Golden Lock Essence-Securing Pill (金锁固精丸jīn suǒ gù jīng wán) containing complanate astragalus seed (Astragali Complanati Semen, 沙苑子shā yuàn zǐ), euryale (Euryales Semen, 芡实qiàn shí), dragon bone (Mastodi Ossis Fossilia, 龙骨lóng gǔ), and oyster shell (Ostreae Concha, 牡蛎mǔ lì) treats kidney vacuity with seminal emission.