In TCM study groups, it is common to hear students inquire about the differences between various formulas, especially the distinctions between decoctions and pills, powders, or granules. I have specifically gathered information and organized it, and today we will thoroughly clarify these differences based on their main characteristics and preparation methods!
1. Decoctions (汤剂, tang ji) are liquid preparations made by soaking herbal pieces in water or alcohol, then boiling for a certain period to extract the essence. They are primarily for internal use, but can also be used externally for bathing, steaming, or gargling. The characteristics of decoctions include rapid absorption and quick efficacy, and they can be adjusted according to changes in the patient’s condition, making them suitable for patients with severe or unstable conditions. Li Dongyuan stated: “Decoctions are for expelling major illnesses.” However, the drawbacks of decoctions are the large volume required for consumption, the difficulty in extracting certain active ingredients, and their inconvenience for mass production and portability.
2. Powders (散剂, san ji) are made by grinding herbs into a fine powder and mixing them evenly, resulting in a powdered preparation that can be taken internally or used externally. Internal powders are usually ground into fine powder and taken with warm water; smaller doses can be taken directly, such as Qili San (七厘散); some are made into coarse powder and decocted, known as boiled powders, such as Yin Qiao San (银翘散). The advantages of powders include simple preparation, rapid absorption, saving on herbal materials, and ease of use and transport. Li Dongyuan said: “Powders are for dispersing, used for acute illnesses.” External powders are generally used for topical application, sprinkled on wounds or affected areas, such as Jinhuang San (金黄散) and Shengji San (生肌散); they can also be used for eye drops or throat sprays, such as Babao Eye Medicine (八宝眼药) and Bingqi San (冰砌散). They should be ground into very fine powder to prevent irritation to the wound.
3. Pills (丸剂, wan ji) are solid spherical preparations made by grinding herbs into fine powder or extracting herbal materials and adding suitable binders. Compared to decoctions, pills are absorbed more slowly, have a prolonged effect, save on herbal materials, and are convenient for use and transport. Li Dongyuan said: “Pills are for gradual treatment.” They are suitable for chronic and weak conditions, such as Liu Wei Di Huang Wan (六味地黄丸). However, some pills have strong properties, often made from aromatic or toxic herbs, and are not suitable for decoction, such as An Gong Niu Huang Wan (安宫牛黄丸) and Zhou Che Wan (舟车丸). Common types of pills include honey pills, water pills, paste pills, and concentrated pills.
4. Pastes (膏剂, gao ji) are made by decocting herbs in water or plant oil and removing the residue, resulting in a preparation that can be used internally or externally. Internal pastes include flowing extracts, tinctures, and decoction pastes; external pastes are divided into soft and hard types. Flowing extracts are mostly used to prepare other formulations, such as mixtures, syrups, granules, and tablets.
5. Liquors (酒剂, jiu ji), also known as medicinal wines, are made by soaking herbs in white or yellow wine, or by heating and stewing them, then removing the residue to obtain the liquid for internal or external use. Liquor has properties that invigorate blood circulation, promote dispersal, and enhance the efficacy of herbs, thus commonly used in wind-dispelling and tonifying formulas, such as Fengshi Jiu (风湿酒), Shen Jiu (参药酒), and Wujia Pi Jiu (五加皮酒). Externally, liquors can also dispel wind, invigorate blood, relieve pain, and reduce swelling.
6. Teas (茶剂, cha ji) are made from herbs that are processed into coarse powder or formed into blocks with suitable binders. They are brewed with boiling water or decocted and consumed at irregular intervals. They are mostly used to treat colds, food stagnation, and diarrhea; in recent years, many new products for fitness and weight loss have emerged, such as Wushi Tea (午时茶), Ciwu Jia Tea (刺五加茶), and weight loss tea.
7. Elixirs (露剂, lu ji), also known as medicinal elixirs, are often made from fresh herbs containing volatile components, distilled to create aromatic, clear aqueous solutions. They are generally used as beverages and cooling agents, with common examples being Jin Yin Hua Lu (金银花露) and Qing Hao Lu (青蒿露).
8. Granules (冲剂, chong ji) are made from herbal extracts combined with appropriate excipients or powdered herbs to form dry granules or blocks, which are taken by dissolving in hot water. Granules act quickly, taste pleasant, are small in volume, and are convenient to take, making them popular among patients, with common examples including cold and fever granules.
9. Tablets (片剂, pian ji) are made by mixing herbal powders or extracts with excipients and compressing them into tablet form. Tablets have accurate dosages and small volumes. Bitter or unpleasant-tasting herbs can be coated with sugar to make them easier to take. For drugs that need to be absorbed in the intestines, enteric coatings can be applied to ensure they dissolve in the intestines. Additionally, there are sublingual tablets and effervescent tablets.
10. Syrups (糖浆剂, tang jiang ji) are made by boiling herbs, removing the residue, concentrating the liquid, and adding sugar to create a sweet syrup solution. Syrups are characterized by their sweet taste, small dosage, and rapid absorption, making them suitable for children, such as cough syrups.
11. Oral liquids (口服液, kou fu ye) are liquid preparations made by extracting herbs with water or other solvents and refining them. This preparation combines the characteristics of decoctions, syrups, and injections, offering advantages such as smaller doses, rapid absorption, convenience, and palatable taste. In recent years, they have developed rapidly, especially with the increasing variety of health and tonic oral liquids, such as ginseng royal jelly oral liquid and Qi Ju Di Huang oral liquid.
12. Injections (注射液, zhu she ye), also known as injectable solutions, are sterile solutions, sterile suspensions, or sterile powders for reconstitution made from extracted, refined, and formulated drugs, intended for subcutaneous, intramuscular, or intravenous injection. They have accurate dosages, rapid efficacy, and are suitable for emergencies, unaffected by the digestive system, making them particularly suitable for patients who are comatose or unable to take oral medications, such as Kai Ling Injection (开灵注射液) and Sheng Mai Injection (生脉注射液).
Each of these formulations has its own characteristics, and clinical selection should be based on the patient’s condition and the characteristics of the formulas. Additionally, there are also capsules, moxibustion preparations, poultices, enema preparations, and aerosol preparations.
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Reminder: The above content is for reference only and may not be suitable for all populations; it is recommended to adjust under the guidance of a physician.