Treatise on the Great Elixir 大丹记

Originally attributed to Wei Boyang, this book is suspected to be a pseudonymous work compiled during the Sui or Tang Dynasty. It was recorded in both the General Catalog of Chongwen Library and the Tongzhi·Bibliography of the Song Dynasty. Consisting of one volume, it is included in the Methods category of the The Dongshen Section in The Daozang.

This work elaborates on External Alchemy. It first discusses the properties of lead and mercury, stating: "The dragon refers to mercury." Mercury originates from cinnabar, belongs to metal, is cold in nature, and is produced in the southern region—occupying the "position of Yin within Yang" and corresponding to the Li trigram. "The tiger refers to silver." Silver originates from lead, belongs to stone, is hot in nature, and is produced in the northern region—occupying the "position of Yang within Yin" and corresponding to the Kan trigram. Refining silver from lead involves lead sinking and silver floating, a product called Yellow Sprout (Huangya). Yellow Sprout, with a solitary Yang nature and hot property, is unfit for ingestion: "It must be combined with mercury to form Male-Female Yellow Sprout (Cixiong Huangya)."

The book also records The Elbow Secret Formula for True Lead, True Mercury, Medicinal Ingredients, and Cauldrons, stating that true lead and true mercury are the essences of the sun and moon, also known as Dragon-Tiger, Kan-Li, Yin-Yang, and Husband-Wife. When these two substances are placed together in an earthen cauldron, they can be nurtured and refined into an elixir. "Those who ingest it will attain longevity; gold, silver, copper, iron, tin, soil, wood, tiles, stones, and other materials will all be transformed into treasures."