Introduction
Traditional Chinese Medicine (TCM) decoctions refer to liquid preparations obtained by boiling Chinese herbal pieces in water to extract their active ingredients, and they are one of the traditional forms of TCM. As stated in the Compendium of Materia Medica: “When taking decoctions, even if the herbs are of high quality and the preparation is done correctly, if the brewing is done carelessly, with improper water and fire, or if the timing is off, the medicine will be ineffective.” This indicates that the quality of decoctions is closely related to the utensils used for brewing, the amount of water, the heat, the timing, and the method. Below, I summarize the conventional brewing methods for traditional Chinese medicine decoctions to better utilize TCM resources for disease prevention and treatment.
1. Conventional Decoction Brewing Methods
1. Water for Decoction: Water that meets drinking water standards is sufficient.
2. Amount of Water for Decoction: The amount of water added depends on the texture and water absorption of the herbs, generally enough to submerge the herbs by 3-5 cm. For the second decoction, a smaller amount of water can be used, just enough to exceed the herb residue by 1-2 cm.
3. Soaking the Herbal Pieces: Before brewing, soak the herbal pieces. For aromatic herbs that are volatile or easily absorbent, cool water should be used for soaking; for hard, sticky herbs that do not contain volatile components, warm water is preferable. Generally, water above 60°C should not be used for soaking, as this aids in the dissolution and extraction of the active ingredients. Soak in cold water at room temperature for 20-30 minutes before brewing to allow for full extraction of the active components. Decoctions primarily made from flowers, leaves, and stems should have a shorter soaking time, while those made from roots, rhizomes, and seeds should be soaked longer.
4. Choice of Brewing Utensils: It is best to use a clay pot; ceramic, enamel, or stainless steel can also be used. Avoid using metal containers for brewing. For example, using an iron pot to brew hawthorn or wutou (Aconitum) can produce insoluble iron tannate, affecting the efficacy of the decoction.
5. Brewing Time and Frequency: The brewing time for decoctions should be determined by the nature of the herbs. Each decoction typically extracts about 45% of the active ingredients in one brewing. This means that after three brews, approximately 90% of the active ingredients have been extracted. If the herbs are only brewed 1-2 times, the total loss of active ingredients can be 30%-55%, especially for tonifying herbs, so it is recommended to brew twice. The first brew should be for 20-30 minutes after the water boils, while the second brew can be slightly shorter, around 15-20 minutes. Herbs for relieving exterior conditions and aromatic herbs should not be boiled for too long, generally 15-20 minutes after boiling, while tonifying herbs and hard-textured herbs require longer, about 40-60 minutes, with the second brew being slightly shorter.
6. Heat Control During Brewing: Use “strong fire” (high heat) before boiling; after boiling, switch to “gentle fire” (low heat) to maintain a gentle boil. Stir frequently during brewing to prevent the decoction from boiling over or burning.
7. Amount of Decoction: Filter the brewed decoction to retain the liquid. The typical dosage for children is 100-300 ml per dose; for adults, it is 400-600 ml per dose, divided into two equal parts for morning and evening consumption, or according to the physician’s prescription.
2. Special Brewing Methods for Specific Herbal Pieces in Prescriptions
For any herbs specified by the physician as “pre-boiled,” “added later,” “wrapped for brewing,” “melted,” “brewed separately,” “taken with water,” “mixed with water,” “brewed as tea instead of water,” or “juiced,” follow the specified instructions.
1. “Pre-boiled” Herbs and Brewing Methods
Pre-boiled herbs include: raw oyster (Sheng Mu Li), calcined oyster (Duan Mu Li), raw dragon bone (Sheng Long Gu), calcined dragon bone (Duan Long Gu), raw dragon teeth (Sheng Long Chi), vinegar turtle shell (Cu Bie Jia), tortoise shell (Gui Ban), raw purple quartz (Sheng Zi Shi), and others as per physician’s advice.
Brewing method: Boil the pre-boiled herbs for 30-35 minutes before adding the other herbs to brew together.
2. “Added Later” Herbs and Brewing Methods
Added later herbs include: mint (Bo He), fresh mint (Xian Bo He), fresh patchouli (Xian Huo Xiang), fresh perilla leaves (Xian Zi Su Ye), sand ginger (Sha Ren), cardamom (Dou Kou), vine tea (Gou Teng), senna leaves (Fan Xie Ye), and agarwood (Chen Xiang), or as per physician’s advice.
Brewing method: Add the later herbs 5-10 minutes before the other herbs are fully brewed.
3. “Wrapped for Brewing” Herbs and Brewing Methods
Wrapped for brewing herbs include: plantago seeds (Che Qian Zi), xuanfu flower (Xuan Fu Hua), silkworm excrement (Can Sha), shepherd’s purse seeds (Ting Li Zi), sea silk (Hai Jin Sha), indigo (Qing Dai), daihua powder (Dai He San), raw cattail pollen (Sheng Pu Huang), fried cattail pollen (Chao Pu Huang), and catechu (Er Cha), or as per physician’s advice.
Brewing method: Place the herbs in a pure cotton bag and brew with the other herbs.
4. “Melted” Herbs and Brewing Methods
Melted herbs include: donkey-hide gelatin (A Jiao), antler glue (Lu Jiao Jiao), tortoise shell glue (Gui Jia Jiao), soft-shelled turtle glue (Bie Jia Jiao), and the dual immortals glue (Gui Lu Er Xian Jiao), or as per physician’s advice.
Brewing method: Add the herbs to an appropriate amount of hot water or heat to melt, then mix with the brewed decoction for consumption.
5. “Brewed Separately” Herbs and Brewing Methods
Brewed separately herbs include: wild ginseng (Ye Shan Ren Shen), ginseng (Ren Shen), red ginseng (Hong Ren Shen), American ginseng (Xi Yang Shen), deer antler slices (Lu Rong Pian), antelope horn slices (Ling Yang Jiao Pian), saffron (Xi Hong Hua), and cordyceps (Dong Chong Xia Cao), or as per physician’s advice.
Brewing method: Place the herbs that need to be brewed separately in a suitable pot, add an appropriate amount of water, and brew alone for 1-2 hours, then filter the liquid and combine it with the decoction for consumption.
6. “Taken with Water” Herbs and Consumption Methods
Taken with water herbs include: notoginseng powder (San Qi Fen), antelope horn powder (Ling Yang Jiao Fen), agarwood powder (Chen Xiang Fen), amber powder (Hu Po Fen), pearl powder (Zhen Zhu Fen), cinnabar powder (Zhu Sha Fen), bear bile powder (Xiong Dan Fen), and deer antler powder (Lu Rong Fen), or as per physician’s advice.
Consumption method: Take with a small amount of warm water or mix with the decoction.
7. “Mixed with Water” Herbs and Consumption Methods
Mixed with water herbs include: xuanming powder (Xuan Ming Fen), bamboo juice (Zhu Li Shui), bamboo extract (Zhu Li Gao), ginger juice (Sheng Jiang Zhi), yellow wine (Huang Jiu), honey (Feng Mi), or as per physician’s advice.
Consumption method: No need to brew, mix into the brewed decoction for consumption.
8. For other special requirements, follow the prescription instructions.
9. If there are any other questions or concerns, feel free to consult the dispensing staff.
3. Correct Medication and Precautions
It is best to filter the brewed decoction immediately. The typical dosage for children is 100-300 ml per dose; for adults, it is 400-600 ml per dose, mixed and taken in portions. If the liquid is too much, the mixed decoction can be concentrated over high heat before consumption. It is best to brew and consume on the same day. If using vacuum-packed decoctions, follow the storage instructions and consume as soon as possible.
1. How to Take After Brewing?
(1) Temperature of the decoction: Depending on the condition.
Warm consumption: Most decoctions should be taken warm, especially those that may irritate the gastrointestinal tract. Cold consumption: Allow the brewed decoction to cool before taking. Generally, cold decoctions are suitable for heat conditions. Hot consumption: Take the brewed decoction while hot. Generally, hot decoctions are suitable for cold conditions. For example, when experiencing wind-cold, it is essential to take it hot, cover up, and eat hot porridge to promote sweating, thus enhancing the medicinal effect.
(2) Dosage of the decoction
Specific dosages depend on the physician’s advice and the condition, with some requiring divided doses (taken multiple times) and others requiring a single dose (taken all at once).
2. When to Take the Decoction?
Decoctions are generally taken once daily, divided into two doses for morning and evening. Whether to take before or after meals mainly depends on the location and nature of the condition: generally, conditions above the chest (heart, lungs), such as sore throat, cold, headache, and dizziness, should be taken after meals, while conditions below the chest (stomach, liver, kidneys) should be taken before meals. Some herbs that may irritate the gastrointestinal tract should be taken after meals, while tonifying herbs should be taken on an empty stomach, and sedative herbs should be taken before sleep. Special formulas should follow the physician’s advice.
3. Precautions
When taking TCM decoctions, avoid smoking and alcohol, and refrain from spicy, oily, greasy, and raw cold foods. Avoid overeating. Patients with skin diseases should avoid fish, shrimp, and stimulating foods. If taking Western medicine concurrently, space out the timing of the doses. Children, pregnant women, or the elderly should follow the physician’s advice.
The author of this article is: Luan Fei from the Pharmacy Department of Weiyang District Traditional Chinese Medicine Hospital, Xi’an.