The purpose of decoction is to transfer the active ingredients in the medicine into the soup through physical and chemical effects (such as dissolution, diffusion, permeation and desorption). The correct decoction of Chinese medicine is also an important part of the therapeutic effect of Chinese medicine. Xu Lingli, a medical doctor of the Qing Dynasty, said, “The method of decoction is the most important thing to talk about, because the effectiveness or ineffectiveness of the medicine lies in this”. In order to make the application of Chinese medicine more reasonable and its efficacy more reliable, the following aspects of decoction of Chinese medicine should be paid attention to. Many people think that the lid should be covered when decocting herbal medicines, but in fact, the effect of cooking different herbs open or covered is really different. For example, some herbal ingredients contain certain volatile components, such as mint, sophora, patchouli, with orchids, which can easily dissipate into the air during the decoction process, so they must be boiled with the lid on, otherwise the medicinal effect will unknowingly run away a lot. Valuable herbs such as American ginseng also have volatile components and need to be decocted in an airtight container. However, for example, the ingredients of Xia Gu Cao, Qian Qian Cao and Silphium are light and take up a large volume, plus some home decoction equipment has a small volume, so if you cover the lid and cook, the liquid will easily spill out, so it is best to open the lid and decoct, but stir from time to time. Time Most Chinese medicines can be decocted for 30 minutes, but decocted medicines can be decocted for 10 minutes, and tonic medicines can be decocted slowly for 40 minutes; mineral, shell and toxic Chinese medicines can be decocted for more time, for example, aconite is extremely toxic, which can be destroyed by water decoction for three or four hours. Soaking Some people think it is superfluous to soak herbal medicines in cool water. In fact, most herbal medicines are dried tissues of plants or animals, and their active ingredients and therapeutic components are distributed in the dried and shrunken cells. Soaking in cool water for half an hour first can make the herbs soften and swell. As the water temperature increases during decoction, the highly concentrated solution inside the tissue will diffuse outside the tissue and the herbs further swell, ensuring that all the active ingredients are dissolved in the water. Direct decoction with boiling water will cause the proteins and starch in animal and plant cells to coagulate and toughen, and water will not easily penetrate and dissolve, resulting in the inability to release the active ingredients and reducing the efficacy of the medicine. At the same time, cool water soaked herbs can shorten the decoction time, such as the usual 2 hours of decoction tonic, only need to reach the boiling point and then decoction for half an hour. Nowadays, some people like to use iron pots to decoct herbs because they are convenient and easy to clean, but in fact, this practice has a great impact on the effectiveness of the medicine. Because many botanicals are acidic or alkaline, neutral ones are rare, and these botanicals contain tannin, organic acids, etc. by composition, which can have a chemical reaction with the iron ions in the iron pot and may produce side effects. For example, chebulo and sumac will react with the iron pot to produce water-insoluble iron tannate, and herbs containing flavonoids can also produce chemical reactions when they encounter iron ions, leading to changes in the composition of the herbs, affecting the decoction and absorption of the herbs and making them less effective. This is because the bottom of the casserole is very evenly heat-conducting, so the “heat” is more moderate, and the insulation of the whole pot is stronger, so the amount of water evaporation is smaller, which is conducive to the preservation of heat-resistant ingredients, and the pharmaceutical ingredients are more comprehensively preserved to ensure that many herbs that are not resistant to high temperatures are not lost. And decoction with a tile pot, in fact, there is a shortcoming, because the tile pot is made of clay, easy to absorb a variety of drug ingredients into the tile pot material inside, and then cook other herbs from time to time there is a string of flavor situation, thus affecting the effectiveness of the medicine. False boiling As we all know, decoction of Chinese medicine should be boiled, but some special Chinese medicine may begin to produce bubbles at low temperatures, and actually did not boil. For example, for Chinese medicines containing saponin and other chemical ingredients, a large number of bubbles can be produced at low temperature, resulting in “false boiling”. In addition, if there are aster, dong hua, farmer’s wisdom, sage, tian qi, niu qi, licorice, orris, etc. in the soup, this phenomenon may also occur during the decoction. If the Chinese medicine is not boiled, the active ingredients in the medicine will not be completely leached out, which will not only fail to achieve the expected effect in clinical practice, but also cause other problems, so care should be taken in the decoction. Nowadays, many people use tap water when decocting herbs, but this is also inappropriate. This is because tap water usually contains residual chlorine, especially in areas where the water quality is poor and the residual chlorine content is higher. Chlorine is a strong oxidizing agent and can react with several organic substances. Only when tap water is boiled to become boiling water can the residual chlorine evaporate away, which avoids the destruction of the active ingredients in Chinese medicine by residual chlorine; and in the process of boiling water, the bicarbonate of calcium and magnesium in tap water decomposes and precipitates, reducing the chance of their combination with the active ingredients in the herbs to precipitate and improve the therapeutic effect of the medicinal juice. Therefore, decoction of Chinese medicine should be made with cool boiled water that has been boiled and then cooled down.