Prepared Rehmannia is a tonic herbal medicine first recorded in *Ben Cao Shi Yi* (Supplement to the Materia Medica). It is the dried tuberous root of *Rehmannia glutinosa Libosch.* (family Scrophulariaceae), processed through specific preparation methods. It is primarily produced in Henan, Liaoning, Hebei, Shandong, and Zhejiang.Prepared Rehmannia has the effects of nourishing blood and yin, as well as replenishing essence and marrow. It is primarily used to treat blood deficiency and liver-kidney yin deficiency, thereby alleviating symptoms such as palpitations, irregular menstruation, soreness and weakness in the lower back and knees, and bone-steaming hot flashes.
Prepared Rehmannia
Prepared Rehmannia is a tonic herbal medicine first recorded in *Ben Cao Shi Yi* (Supplement to the Materia Medica). It is the dried tuberous root of *Rehmannia glutinosa Libosch.* (family Scrophulariaceae), processed through specific preparation methods. It is primarily produced in Henan, Liaoning, Hebei, Shandong, and Zhejiang.Prepared Rehmannia has the effects of nourishing blood and yin, as well as replenishing essence and marrow. It is primarily used to treat blood deficiency and liver-kidney yin deficiency, thereby alleviating symptoms such as palpitations, irregular menstruation, soreness and weakness in the lower back and knees, and bone-steaming hot flashes.
Chinese Name : 熟地黄
Latin Name : Rehmanniae Radix Praeparata
Aliases : Shu Di Huang, Da Shu Di Huang, Sha Shu Di Huang
Authentic Producing Area : Jiaozuo, Henan
Nature, Flavor & Meridian Tropism : Slightly warm in nature, sweet in taste; enters the Liver and Kidney meridians
Benefits & Efficacy
Benefits
Prepared Rehmannia Root is slightly warm in nature, sweet in taste, and enters the Liver and Kidney meridians. It has the effects of nourishing blood and yin, and replenishing essence and marrow.
Indications
1. Prepared Rehmannia Root is primarily used to treat blood deficiency syndrome, characterized by a sallow complexion, dizziness, palpitations and anxiety, irregular menstruation, and abnormal uterine bleeding such as metrorrhagia and menorrhagia. 2. Prepared Rehmannia Root is primarily used to treat liver and kidney yin deficiency syndrome, characterized by soreness and weakness in the lower back and knees, bone-steaming fever and night sweats, nocturnal emissions, internal heat and excessive thirst, dizziness and tinnitus, and premature graying of hair.
Usage and Dosage
Take 9–15 g as a decoction; or incorporate into pills or powders; or prepare as a paste or infuse in wine.
Precautions
Prepared Rehmannia has a rich and heavy nature and may impair digestion; therefore, use with caution in patients with spleen-stomach deficiency, abdominal distension with loose stools, or qi stagnation with excessive phlegm.
Chemical Constituents
Rehmannia glutinosa primarily contains styrenoside compounds (such as trichoside) as well as monosaccharides and various amino acids.
Pharmacological Actions
Rehmannia glutinosa promotes hematopoiesis, lowers blood sugar, enhances memory, and boosts immunity.
Applications
Related Compatibility
1. Prepared Rehmannia combined with Cornus officinalis. Prepared Rehmannia excels at tonifying the liver and kidneys, nourishing blood, and enriching essence; Cornus officinalis excels at warming and tonifying the liver and kidneys, reducing urination, and consolidating essence.When used in combination, these two herbs enhance the effects of nourishing the kidneys and yin, as well as consolidating and retaining essence and vital energy. This combination is suitable for treating symptoms such as dizziness, vertigo, tinnitus, deafness, soreness and weakness in the lower back and knees, erectile dysfunction, nocturnal emissions, and night sweats caused by liver and kidney yin deficiency.
2. Prepared Rehmannia Root combined with Chinese Yam. Prepared Rehmannia Root excels at replenishing blood, nourishing yin, replenishing essence, and nourishing the marrow;Chinese yam excels at tonifying the kidneys and consolidating essence, as well as tonifying the spleen and nourishing yin. When used in combination, these two herbs enhance the effects of nourishing yin, tonifying the kidneys, and consolidating essence to stop seminal emission. This combination is suitable for treating conditions such as seminal emission and enuresis caused by kidney deficiency.
3. Prepared Rehmannia Root combined with White Peony Root. Prepared Rehmannia Root excels at replenishing blood, nourishing yin, replenishing essence, and enriching marrow; White Peony Root excels at nourishing blood, consolidating yin, soothing the liver, and relieving pain.When used in combination, these two herbs enhance the effects of nourishing yin, tonifying the kidneys, and replenishing and nourishing blood. This combination is suitable for treating irregular menstruation, blurred vision, and impaired visual acuity caused by liver blood deficiency or liver-kidney deficiency.
4. Prepared Rehmannia Root combined with Asarum. Prepared Rehmannia Root excels at replenishing blood and nourishing yin, while Asarum excels at dispelling wind and dispersing cold. When used together, they enhance the effects of tonifying the kidneys and dispelling cold, making this combination suitable for treating lower back pain caused by kidney deficiency.
5. Prepared Rehmannia Root combined with Mulberry Parasite. Prepared Rehmannia Root excels at replenishing blood, nourishing yin, replenishing essence, and enriching marrow; Mulberry Parasite excels at tonifying the liver and kidneys, nourishing blood, and stabilizing the fetus. When used together, they enhance the effects of tonifying the kidneys, replenishing essence, nourishing blood, and stabilizing the fetus. This combination is suitable for conditions such as fetal restlessness caused by deficiency of liver and kidney essence and blood.
6. Prepared Rehmannia Root combined with Schisandra Berry. Prepared Rehmannia Root excels at tonifying the kidneys and replenishing essence, while Schisandra Berry excels at consolidating the lungs and nourishing the kidneys. When used together, they enhance the effects of tonifying the kidneys, anchoring qi, consolidating the lungs, and relieving cough, making this combination suitable for coughing, shortness of breath, and a condition characterized by more exhalation than inhalation caused by deficiency of both the lungs and kidneys.
Medicinal Identification
Clear-steamed Rehmannia, wine-processed Rehmannia, and charred Rehmannia are products of Rehmannia root prepared through different processing methods. Among these, clear-steamed Rehmannia is made by steaming raw Rehmannia root; it has a thick consistency and strong flavor, with its nature changing from cold to warm, its taste shifting from bitter to sweet, and its function transitioning from clearing to tonifying. It primarily serves to nourish blood, nourish yin, and replenish essence and marrow, but it still has the drawback of being greasy and potentially hindering the spleen;Wine-processed Rehmannia has a warm nature and primarily tonifies yin and blood. Furthermore, the action of the wine helps disperse the properties of the herb, promoting the circulation of medicinal effects and unblocking the blood vessels, which is more conducive to blood tonification and ensures that the tonic effect is achieved without causing greasiness; whereas charred Rehmannia primarily focuses on tonifying blood and stopping bleeding, and is often used to treat metrorrhagia and menorrhagia or deficiency-type bleeding.
Related Medicines
Liuwei Dihuang Pills, Gui Sha Dihuang Pills, Weixue Ning Granules, Jian Yanling Capsules, Huan Shao Capsules, and Menopausal Calming Capsules, among others.
Related Prescriptions
Siwu Decoction (*Secret Formulas for Treating Injuries and Fractures Transmitted by Immortals*), Liuwei Dihuang Pills (*Direct Decisions on Pediatric Medicines and Syndromes*), Dihuang Decoction (*Comprehensive Record of Holy Remedies*), Zuogui Pills (*Complete Works of Jingyue*), Dabuyin Pills (*Danxi’s Heart Methods*),Jiao Ai Decoction (*Jin Gui Yao Lue*), Ba Zhen Decoction (*Zheng Ti Lei Yao*), Zhi Bai Di Huang Pills (*Yi Fang Kao*), etc.
Notes
Patients requiring treatment with traditional Chinese medicine should first consult a licensed TCM hospital, where a TCM practitioner will conduct a professional diagnosis and prescribe the appropriate herbal formula.
Processing & Preparation
Harvesting & Processing
Harvest in the fall. Remove the root crown, fibrous roots, and any mud or sand. Simmer using the wine-simmering method until all the wine has been absorbed; remove the material, sun-dry until the mucilage on the outer skin is slightly dry, then cut into thick slices or chunks and dry thoroughly; or steam until black and lustrous, remove, sun-dry until approximately 80% dry, then cut into thick slices or chunks and dry thoroughly.
Processing Methods
1. Steamed Prepared Rehmannia. Take clean raw Rehmannia root, place it in a wooden steamer, steamer basket, or other suitable container, and steam over heat until both the interior and exterior are black and lustrous. Remove, sun-dry until about 80% dry, cut into thick slices, and dry thoroughly.
2. Wine-processed Rehmannia. Take cleaned raw Rehmannia root, mix thoroughly with yellow wine, place in a medicinal stew pot, seal tightly, and heat over a water bath until thoroughly stewed; or place in a suitable container and steam until the surface is black and glossy and the yellow wine is completely absorbed. Remove, sun-dry until the outer skin is slightly dry, cut into thick slices, and dry. Use 30–50 kg of yellow wine per 100 kg of raw Rehmannia root.
3. Ginger-Processed Prepared Rehmannia. Take fresh ginger, wash it, and pound it into a paste. Add 5 kg of water and pound thoroughly to extract the juice. Pour the ginger juice into a vat, add ground Amomum villosum, white liquor, and the Rehmannia juice, then stir well with a wooden stick.then immediately place the sun-dried prepared rehmannia root into the vat. Turn it repeatedly to mix thoroughly, ensuring the ingredients fully coat the root. Transfer the mixture to a steamer and steam for 4 hours, until it turns black, tastes sweet like malt syrup, and emits a rich aroma; remove and sun-dry or dry over low heat.For every 100 kg of raw Rehmannia root, use 5 kg of white liquor, 3 kg of ginger (with 5 kg of water added), 1 kg of ground amomum, and 10 kg of prepared Rehmannia juice.
4. Preparing Prepared Rehmannia Root with Amomum.Take clean raw Rehmannia root, mix with rice wine and ground amomum, and place the mixture in a copper pot or other suitable container. Seal tightly, heat over high heat, and steam in a water bath for approximately 48 hours until the root is jet-black inside and out and becomes hollow. Remove, air-dry until 80% dry, cut into thick slices, and dry thoroughly. For every 100 kg of raw Rehmannia root, use 30–50 kg of rice wine and 1 kg of ground amomum.
5. Charred Prepared Rehmannia Root. Place slices of prepared Rehmannia root in a wok and stir-fry over high heat until they puff up, the surface turns charred black, and the interior turns charred brown. Sprinkle a small amount of water over them, then continue stir-frying until all moisture has evaporated. Transfer to a suitable container, cover tightly, and ensure all embers are extinguished. Remove and allow to air-dry until completely cool.
Storage Methods
Store in a dry container. Keep all processed forms of prepared Rehmannia root tightly sealed and place in a cool, dry location to prevent mold and insect infestation. Charred Prepared Rehmannia root should be kept away from heat to prevent reignition.
Crude Drug Identification
Identification
Take 1 g of the powdered sample, add 50 mL of 80% methanol, subject to ultrasonic treatment for 30 minutes, filter, and evaporate the filtrate to dryness. Dissolve the residue in 5 mL of water, extract four times with 10 mL of water-saturated n-butanol each time, combine the n-butanol extracts, and evaporate to dryness. Dissolve the residue in 2 mL of methanol to prepare the test solution.Separately, take a reference standard of trichosanthin glycoside and dissolve it in methanol to prepare a solution containing 1 mg per mL; use this as the reference solution.Perform the test according to the thin-layer chromatography method (General Chapter 0502). Pipette 5 μL of the test solution and 2 μL of the reference solution, and apply them separately onto the same silica gel G thin-layer plate. Develop with a mobile phase of ethyl acetate–methanol–formic acid (16:0.5:2),remove the plate, allow it to air-dry, impregnate with a 0.1% solution of 2,2-diphenyl-1-hydrazine in anhydrous ethanol, and allow it to air-dry. In the test chromatogram, spots of the same color as those in the reference standard chromatogram should appear at the corresponding positions.
Properties of Processed Slices
1. Steamed Rehmannia root appears as irregular chunks or fragments of varying sizes and thicknesses. The surface is jet-black, glossy, and highly viscous. It is soft yet resilient, not easily broken; the fracture surface is jet-black and glossy. It has a faint odor and a sweet taste.
2. Wine-processed Rehmannia root resembles steamed Rehmannia root and has a slight wine-like odor.
3. Ginger-processed prepared Rehmannia root resembles steamed prepared Rehmannia root; it has a sweet taste like malt syrup and a strong aroma.
4. Amomum-processed prepared Rehmannia root resembles steamed prepared Rehmannia root and is jet-black in color.
5. Charred prepared Rehmannia root resembles steamed prepared Rehmannia root; its surface is charred black and glossy. It is light in texture and swollen; the outer skin is charred and brittle, with honeycomb-like fissures in the center, and it has a charred, sweet taste.
Botanical Information
Botanical Classification
A plant of the genus Rehmannia in the Scrophulariaceae family.
Morphological Characteristics
Perennial herb. The rhizome is stout and fleshy. Axillary racemes bear large, pale reddish-purple flowers; the calyx is bell-shaped, and the corolla is tubular and curved, varying in color. The capsule is spherical to oval. Flowering occurs from April to June, and fruiting from July to August.
Distribution Area
Rehmannia glutinosa is primarily distributed in Henan, Liaoning, Hebei, Shandong, and Zhejiang.
Growth Habits
Rehmannia glutinosa prefers a warm, humid climate and ample sunlight; it is tolerant of severe cold and drought but cannot tolerate waterlogging. It is highly adaptable and resilient, capable of growing in most types of soil.