Chinese herbal decoctions have the advantages of fast absorption, easy therapeutic effect, and convenient modification in clinical practice. Decoctions are the earliest and most widely used dosage form in traditional Chinese medicine. However, the process of decocting herbs is very important, including the steeping time and the amount of water added during decoction.
[Importance of Decoction Time]
1. Pre-soaking: The herbs should be soaked for 30 minutes before the first decoction. Seeds and fruit-based herbs can be soaked for one hour. No further soaking is necessary for subsequent decoctions. The water level for the first decoction should be 2-5 centimeters above the herbs, and for the second decoction, the water level should just cover the herbs.
2. Number of decoctions: Generally, two decoctions are recommended. One long decoction cannot replace two separate decoctions.
3. Decoction heat: Use high heat (strong flame) before boiling, and low heat (gentle flame) after boiling to maintain a slight boil. For herbs with a dispersing and aromatic nature, rapid boiling is recommended to prevent the evaporation and loss of medicinal properties. For tonic herbs, slow simmering is preferred to fully extract the active ingredients.
4. Decoction time: For most herbs, the first decoction should be boiled for 20-25 minutes on low heat after boiling, and the second decoction should be boiled for 15-20 minutes. For herbs with dispersing and aromatic properties, the first decoction should be boiled for 10-15 minutes, and the second decoction for 10 minutes. For tonic herbs, the first decoction should be boiled for 30-40 minutes, and the second decoction for 25-30 minutes.
Decoction time should be determined based on the nature of the herbs and the disease, as well as the condition of the herbs.
[Importance of Water Quantity in Decoction]
The ideal water level should be 2-7.5 centimeters above the herbs or just enough to cover the back of your hand when lightly pressed against the herbs.
1. Some flowers and herbal medicines have high water absorption and the water level may decrease after soaking for half an hour. In this case, additional cool water can be added to reach the standard water level before decoction.
2. The quantity of water directly affects the quality of the decoction. Insufficient water can result in incomplete extraction of active ingredients. Excessive volume of decoction makes it inconvenient for patients to take the medicine.
3. Different herbal medicines have different water absorption capacities due to their different textures. The water quantity should generally be controlled at 5-10 times the weight of the herbs. Herbs with loose texture have larger volume and higher water absorption. Herbs with solid texture have smaller volume and lower water absorption.
Therefore, flowers, leaves, and whole herb medicines require more water. Mineral and shell-based medicines require less water.
4. According to traditional methods, the herbs should be placed in a pot. The water level for the first decoction should be 3-5 centimeters above the herbs, and for the second decoction, 3 centimeters above the herbs. This method is simple and easy to master.
[Two Precautions for Decoction]
1. Clean the decoction pot thoroughly
During the decoction process, the herbal juice evaporates and concentrates, leaving a layer of herbal residue at the bottom and around the pot. If the herbs in the pot are frequently changed without timely cleaning of the residue, the residue will dissolve and interfere with the efficacy of the decoction, and even delay the treatment. Especially if strong toxic herbs or externally used herbs that should not be ingested have been decocted previously, it may cause poisoning.
In addition, if the pot is not cleaned promptly after each decoction, the herbal residue at the bottom will accumulate and become thicker, increasing the risk of burning and loss of medicinal efficacy during subsequent decoctions.
2. "Decoction until fully cooked" and "squeeze out the liquid"
"Decoction until fully cooked" means to fully release the active ingredients of the herbs. This is the basic requirement for decoction. For herbs with tough texture that are difficult to release the active ingredients, additional decoctions, first decoction, or long decoction are needed to make the decoction more concentrated and fully exert the medicinal effect. For loose texture and lightly aromatic herbs, they do not need to be decocted for a long time. However, bulky herbs should be stirred frequently to facilitate thorough decoction.
