How many times should a dose of Chinese medicine be boiled?

I believe many people have seen Chinese medicine at home. When decocting Chinese medicine, a strong medicinal aroma will be produced. Therefore, the difference between Chinese medicine and Western medicine is that patients need to take it home and boil it themselves to drink the medicine. However, many Chinese medicines can be decocted more than once, because the medicinal properties of Chinese medicines are not fully exerted after being decocted once, and can be decocted multiple times. But in the process of decocting Chinese medicine, how many times can a dose of Chinese medicine be decocted?

It is generally believed that decocting twice is appropriate. It is better to fry it several times rather than simmer it for a long time at one time.

Decoction is the process of dissolving the ingredients in the medicine. After the crude drug is immersed in the aqueous solution, the drug itself absorbs a part of the water. The alkaloid salts, glycosides, organic acids and organic acid salts, sugars, tannins, proteins, pigments, enzymes and other ingredients contained in the medicine are almost all soluble in water. Although resins and fatty oils are insoluble in water, they can be partially dissolved together with other ingredients, thus causing a concentration difference inside and outside the medicinal material. The effective ingredients seep out from the tissue. When the concentration inside and outside the medicinal material is equal, that is, in a state of equilibrium, the dissolution stops. Because dissolution is a dynamic equilibrium, if the ratio of the active ingredients inside the crude drug to the extract therein is equal to the ratio of the active ingredients outside the crude drug to the external extract, then the drug components cannot be completely dissolved. The drug solution must be filtered out and new solvent water must be added to re-establish the concentration difference. Only in this way can the medicinal components continue to dissolve.

Experiments have shown that boiling a decoction twice can extract 80% to 90% of its ingredients, so it needs to be boiled two or three times.

Some people have made comparative observations on the decoction rates of various medicinal materials, several varieties with different specifications, and the number of decoctions of compound medicines. The results show that the first and second decoctions of single herbs and compound medicines in the experiment accounted for 70% to 80% of the decoction rate, while the third and fourth decoctions accounted for 20% to 30% of the decoction rate. This shows that it is reasonable and necessary to decoct Chinese herbal medicines twice. However, decocting too many times is not a good thing, because some active ingredients of medicines will decompose and hydrolyze after long-term heating, and at the same time, the efficacy of the medicine will be destroyed while dissolving.

The decoction time should be determined according to the nature of the medicine and the disease, the difficulty of dissolution of the active ingredients and the circumstances of medication. Generally speaking, the first decoction takes 20 to 25 minutes starting from boiling, and the second decoction takes 15 to 20 minutes. The first decoction of antipyretic drugs takes 10 to 15 minutes, and the second decoction takes 10 minutes. The tonic first decoction should be boiled for 30 to 40 minutes, the second decoction should be boiled for 25 to 30 minutes. If there is any medicine to be decocted first, it should be decocted for 10 to 30 minutes first, and the later medicine should be put into the pot in the last 5 to 10 minutes.