The Taboo Almanac of Celestial Taiyi 天皇太一神律避秽经

The compiler is unknown, and it is believed to have been written between the Tang Dynasty and Song Dynasty.

Consisting of one volume, it is included in the Zhengyi Section of The Daozang.

This text details methods for selecting auspicious days and avoiding impurities in alchemy. It states that Taoist priests must observe taboos in health preservation and alchemy, and should avoid twelve types of impurities—failure to do so will result in the failure of the elixir. The book lists twelve calendars of impurity avoidance for alchemy. For example, "Impurity of Yin-Yang Conjunction" notes: "In spring, the Dingmao day; in summer, the Jiawu day; in autumn, the Gengshen day; in winter, the Rengui days—these are forbidden for making elixirs." Another example, "Impurity of Jade Maidens' Wandering", states: "On each Liuding day (six specific days in the Taoist calendar), elixir-making is prohibited to avoid the Liuding Maidens." The other ten items follow a similar pattern.