What are the processing methods for Rehmannia? A detailed explanation of the entire Rehmannia processing procedure

Rehmannia is one of the "Four Great Huai Medicines," with a long recorded history. It is cool in nature and sweet-bitter in taste, with the effects of nourishing yin and tonifying the kidney, nourishing and replenishing blood, and cooling blood. Its effects differ according to the processing method. Let us now take a look at the processing methods for Rehmannia!

Fresh Rehmannia

[Processing] When needed, take the fresh raw herb, remove impurities, wash clean, and cut into sections.

[Characteristics] Spindle-shaped or strip-shaped, 8-24 cm long, 2-9 cm in diameter. The outer skin is thin, the surface is light reddish-yellow, with curved longitudinal wrinkles, bud scars, transversely elongated lenticels, and irregular scars. Fleshy, easily broken. The cross-section shows a pale yellowish-white cortex, with visible orange-red oil dots, and a yellowish-white xylem, with vessels arranged radially. Slight odor, slightly sweet and slightly bitter taste.

[Nature and Taste] Sweet, bitter, cold.

[Meridian Tropism] Heart, liver, and kidney meridians.

[Effects] Clears heat and promotes fluid production, cools blood, and stops bleeding. Used for damage to yin from febrile disease, crimson tongue with restlessness and thirst, macules and papules, hematemesis, epistaxis, and sore swollen throat.

Raw Rehmannia

[Processing] Take the raw herb, remove impurities, wash clean, soften by moistening, cut into thick slices, and dry.

[Characteristics] Mostly flat-round thick slices, 2-7 cm in diameter. The surface is grayish-brown to blackish-brown, with irregular wrinkles. The cut surface is brownish-black or brownish-gray, slightly lustrous, and sticky. The texture is relatively soft and tough. Slight odor, slightly sweet taste.

[Nature and Taste] Sweet, cold.

[Meridian Tropism] Heart, liver, and kidney meridians.

[Effects] Clears heat and cools blood, nourishes yin, and promotes fluid production. Used for crimson tongue with restlessness and thirst in febrile disease, yin deficiency with internal heat, steaming bone and consumptive fever, internal heat with wasting-thirst, hematemesis, epistaxis, and macules and papules. Raw Rehmannia charcoal nourishes yin and stops bleeding. Used for various bleeding disorders.

Raw Rehmannia Charcoal

[Processing] Take raw Rehmannia, stir-fry until thick smoke rises and the surface swells and turns charcoal-black while the interior is brown, then spray lightly with water, extinguish all sparks, take out, and air-dry.

[Characteristics] The surface is scorched black, the interior is brown. The texture is loose and brittle. Slight scorched odor, slightly bitter taste.

[Nature and Taste] Sweet, bitter, slightly astringent, cool.

[Meridian Tropism] Heart, liver, and kidney meridians.

[Effects] Clears heat, promotes fluid production, nourishes yin, and nourishes blood. Used for warm-heat disease with heat entering the nutrient and blood levels, with symptoms such as feverish body and dry mouth, and crimson or red tongue.

Prepared Rehmannia

[Processing] Take raw Rehmannia softened by moistening with water, place it in a suitable container, steam for about 6-8 hours, let it steep overnight, until it is moist and black both inside and outside, then take it out, air-dry until 70-80% dry, and dry.

[Characteristics] Entirely moist and black, lustrous. The texture is soft yet somewhat resilient, not easily broken, and highly sticky. Sweet taste.

[Nature and Taste] Sweet, slightly warm.

[Meridian Tropism] Liver and kidney meridians.

[Effects] Nourishes yin and replenishes blood, benefits essence and fills marrow. Used for yin deficiency of liver and kidney, soreness and weakness of waist and knees, steaming bone and tidal fever, night sweats and seminal emission, internal heat with wasting-thirst, blood deficiency with sallow complexion, palpitations and severe palpitations, irregular menstruation, uterine bleeding, dizziness, tinnitus, and premature graying of beard and hair. Prepared Rehmannia charcoal replenishes blood and stops bleeding. Used for deficiency damage of the thoroughfare and controlling vessels, and uterine bleeding.

Prepared Rehmannia Charcoal

[Processing] Take prepared Rehmannia, stir-fry until thick smoke rises and the surface swells and turns scorched black while the interior is brown, then spray lightly with water, extinguish all sparks, take out, and air-dry.

[Characteristics] The surface is scorched black, the interior is dark brown, and the texture is relatively loose and brittle. Slight scorched odor, slightly bitter taste.

[Nature and Taste] Sweet, slightly astringent, slightly warm.

[Meridian Tropism] Liver and kidney meridians.

[Effects] Nourishes yin and replenishes blood, benefits essence and fills marrow.