Historical evolution and processing mechanism of ‘nine steaming and nine drying’ of traditional Chinese medicine preparation

Figures & data

Table 1. Historical evolution of four typical TCM processed by nine steaming and nine drying.

Variety of medicinal materials	Dynasty	Ancient medical literature	The record of ‘nine steaming nine drying’
Sesamum indicum L. (Pedaliaceae) seed (Huma)	Southern and Northern Dynasties	Annotations on the Classic of Materia Medica	Nine steaming, nine sun-exposing, frying, and pounding, if not steamed well, it can cause hair loss
	Tang Dynasty	Beiji Qianjin Yaofang	Steam thirty times, bake and grind
	Tang Dynasty	Newly Revised Materia Medica	Nine steamed and nine exposed, stir fried, mashed
	Song Dynasty	Bencao Tujing	To eat its fruit, it should be steamed, exposed to sun nine times, fried, and mashed
	Ming Dynasty	Primitive Materia Medica	Take black sesame, steam and sun nine times, stir fry and mash before taking
	Qing Dynasty	Materia Medica Description	Nine steams and nine exposures, then sunlight three times combined with Maoshan Atractylodes macrocephala and milk, can strengthen the spleen, dry dampness, and replenish qi
	Qing Dynasty	Wo Ling Materia Medica	Flax is processed using the nine steaming and nine drying method, and prepared into a pill with jujube paste. After taking it, white hair returns to black
Polygonatum sibiricum Delar. ex Redoute. (Liliaceae) root (Huangjing)	Tang Dynasty	Herbal Food Medicine	Nine steaming and nine drying
	Song Dynasty	Rihuazi Materia Medica	Nine steaming and nine drying, can nourish the skin after use
	Five Dynasties	Shu ben cao	The best medicinal effect is to take it with nine steamed and nine dried by sunshine, and if it is dried in the shade, it may cause decay
	Ming Dynasty	Herbal for Relief of Famines	Processed using the nine steams and nine storms method, if the degree of processing is not sufficient, it can irritate the throat
	Ming Dynasty	Bencao Mengquan	Nine steamed and nine exposed, can replace grain
	Ming Dynasty	Compendium of Materia Medica	Huangjing and Manjingz steamed nine times and sun dried nine times together
Rehmannia glutinosa(Gaert.) Libosch. ex Fisch. et Mey. (Scrophulariaceae) tuberous root (Dihuang)	Tang Dynasty	Supplement to Invaluable Prescriptions for Ready Reference	The ancient method required nine steaming and nine sun drying. Now, it is observed that the liquid is completely absorbed and the color turns black
	Song Dynasty	Bencao Tujing	Dihuang should be processed until its appearance appears black and shiny, with a high sweetness
	Song Dynasty	Classified Materia Medica	Dried Rehmannia glutinosa after steaming, mixed with Rehmannia liquid, soaked, dried, steamed
	Yuan Dynasty	Decoction and Material Medica	After steaming Rehmannia glutinosa nine times, it can replenish the kidney’s vital energy
	Ming Dynasty	Herbal for Relief of Famines	Nine steamed and nine sun dried
	Ming Dynasty	Compendium of Materia Medica	Steamed and sun dried nine times with Amomum villosum and rice wine
	Qing Dynasty	Materia Medica Description	Rehmannia glutinosa does not achieve its effectiveness through a single process
	Republic of China	Identification of Additional Counterfeit Drug Articles	Rehmannia glutinosa needs to be processed through nine steaming and nine sun drying processes. The transparent black color has good quality, but if the center is slightly yellow, the quality is poor
Fallopia multiflora (Thunb.) Harald. (Polygonaceae) tuberous root (Heshouwu)	Song Dynasty	Peaceful Holy Benevolence Formulae	Nine steaming and nine drying, roasting and mashing
	Song Dynasty	Bencao Tujing	Use after nine steaming and nine sun exposure
	Ming Dynasty	Ben cao pin hui jing yao	Steamed together with dates or black beans
	Ming Dynasty	Compendium of Materia Medica	Use after nine steaming and nine sun exposure
	Ming Dynasty	Bencaohuiyan	Polygonum multiflorum needs nine steaming and nine sun exposure to reduce its toxicity.
	Qing Dynasty	Supplements to Compendim of Materia Medica	Processing Polygonum multiflorum with black beans plays a role in guiding medicine into the kidney meridian

Figure 1. The purpose of nine steaming nine drying drugs - taking polygonum multiflorum as an example.

Figure 2. The characteristics and pharmacological changes of Rehmanniae Radix prepared by nine steaming and nine drying.