According to Henry C. Lu (2) Rehmannia root was traditionally prepared by steaming it ten times and drying it in the sun nine times. Lesley Tierra (3) explains that it is prepared by stirring and steaming in red wine. Both authors explain that it becomes black.
The prepared root is used much differently than the unprepared root, and they are understood to be in different herbal classes. Yellow Earth reduces heat and lubricates dryness while Cooked Yellow Earth corrects deficiencies. (2) Michael Tierra classifies the prepared root as a tonifying/nurturing herb (or blood tonic) in Planetary Herbology. (4) Bensky and Gamble put the prepared root under “Tonifying Herbs” and then under the subcategory “Herbs that Tonify the Blood” and the unprepared root under “Herbs that Clear Heat” and then “Herbs that Cool the Blood” in Chinese Herbal Medicine. (1)
“Sheng Di Huang is used to clear heat and cool the blood; for fevers, bleeding, mouth and tongue sores, dry mouth. Western uses are its ability to inhibit allergic and excessive immune response (auto-immune diseases). It has been used to treat lupus, rheumatoid arthritis, psoriatic arthritis, Sjogren’s syndrome and eczema.” (6) Yellow Earth (Sheng Di Huang) is sweet, bitter, and cold and influences the Heart, Liver, and Kidney channels (meridians and systems). (I) Its main constituents are B-sitosterol, mannitol, stigmasterol, campesterol, rehmannin, catapol, arginine, and glucose. (1) “[It] is used in all Warm-febrile diseases where Heat enters the Nutritive level causing very high fever, thirst, and a scarlet tongue. Also indicated in cases of hemorrhage due to Heat entering the Blood level… [Yellow Earth is also] used to treat patterns of Deficient Yin with Heat signs, as well as injury to the body’s fluids. Manifestations include dry mouth, continuous low-grade fever, and constipation. Also used for Deficient Yin throat pain. [It] cools the upward blazing of Heart Fire [manifested as] mouth and tongue sores… irritability, insomnia, afternoon or low-grade fever, and malar flush [And it is] used for Wasting and Thirsting syndrome.” (1) It is used as a tonic for various cancers associated with dryness, inflammation, and yin deficiency. (5)
Bensky and Gamble contraindicate Yellow Earth in patterns of Damp Phlegm, in Deficient Spleen patterns with Dampness, in patients with Deficient Yang, and in pregnant women with Deficient Blood or Deficient Spleen or Stomach. (1) Tierra contraindicates Yellow Earth and Cooked Yellow Earth during cancer in cases of digestive weakness, explaining that the herbs are heavy and moist and that the primary focus for cancer treatment is to strengthen digestion. (5) Yellow Earth injected intravenously in rabbits and dogs seemed to raise blood pressure, but I found no contraindications for using it in humans with high blood pressure.
Cooked Yellow Earth is used as a blood tonic in deficient blood patterns with pale skin, anemia, insomnia, dizziness, irregular menses and palpitations, and is also a kidney yin tonic and helps to reduce allergic response. (6) It is used in many Chinese formulas, including Women’s Four Herb Tea. (6) Cooked Yellow Earth is sweet and slightly warm with an influence on the Liver, Kidney, and Heart channels and has the same main constituents as its unprepared form. (1) Cooked Yellow Earth Tonifies the Blood and is “used for Deficient Blood patterns with such symptoms as a pallid face, dizziness, palpitations and insomnia. [It is also] used for irregular menstruation, uterine bleeding, and postpartum bleeding. [It also Nourishes the Yin and is] used for Deficient Kidney Yin, with such manifestations as night sweats, nocturnal emissions, Steaming Bone syndrome, and Wasting and Thirsting syndrome.” (1) It also has a traditional use in China to make gray hair return to the normal color. (2) “Prepared rehmannia is one of the few herbs that tonifies Blood, Yin and Essence together.” (3)
Lesely Tierra states that Cooked Yellow Earth’s “only drawback is a very dampening nature, causing difficult digestion with loose stools if taken in excess.” (3) Bensky and Gamble state that the side effects “are mild and include diarrhea, abdominal pain, dizziness, lack of energy, and palpitations.” (1) (I question their following statement: “These symptoms usually disappear on continued administration of the herb.” Do they mean “discontinued”?) Michael Tierra’s contraindications in the case of cancer because of rehmannias’ possible adverse effects on digestion have already been discussed in this paper. He does state, “Nevertheless, because kidney and adrenal deficiency is commonly associated with the after-effects of chemotherapy or with advanced cancer, a small amount of rehmannia may be of great benefit in a carefully balanced formulation.” (5)
Cooked Yellow Earth should be used cautiously in patients with Deficient Spleen and/or Stomach, and Stagnant Qi or Phlegm. (1) “Those with weak digestion yang deficiency and/or stagnation of qi should not use these herbs, especially when there is dampness, as in conditions associated with diarrhea, lack of appetite, and/or excess phlegm. Pregnant women should also avoid it.” (5) “Overuse can lead to abdominal distension and loose stools.” (1)
The dose of both forms is 9 to 30 grams in decoction according to the Tierra’s. (3&5) Lu gives 10 to 90 grams of Yellow Earth and 20 grams of Cooked Yellow Earth. (2) David Winston gives a dose of 30 to 40 drops of the extract of Yellow Earth and 30 to 50 drops of Cooked Yellow Earth. (6) Bensky and Gamble state “3 quian to 1 liang” as the dosage for both forms. (1) Wiseman and Ellis report using Yellow Earth as a decoction of 9 to 15 grams or 30 to 60 grams for a large dose. (7) The decoction can be boiled to a paste and made into pills and powders, it can be charred for bleeding and applied topically crushed. (7) Wiseman and Ellis give 12 – 30 grams decocted as the dose for Cooked Yellow Earth, and list its use in pills and powders, and crude for welling abscess sores and scrofula, and for constipation. (7)
BIBLIOGRAPHY (the page numbers listed refer to the main monographs – information cited otherwise is followed by the page number in the text)
1 Dan Bensky and Andrew Gamble Chinese Herbal Medicine Materia Medica
pages 95-97 and 470-471
2 Henry C. Lu Chinese Natural Cures pages 136-137
3 Lesley Tierra Healing with the Herbs of Life pages 113-114
4 Michael Tierra Planetary Herbology pages 313-314
5 Michael Tierra Treating Cancer with Herbs 81 and 211-212
6 David Winston Herbal Therapeutics page 93
7 Nigel Wiseman and Andrew Ellis Fundamentals of Chinese Medicine
pages 300 and 347