The proper way to decoct Chinese herbal medicines is usually to soak the herbs for 30-40 minutes, then add water and decoct twice, mix the liquid from the two decoctions together and take them in divided doses. However, depending on the herbs used, you should consult your doctor for the exact method of decoction.
Soak the herbs in water first, with the water surface not exceeding 1-2 centimeters of the herbs, for 30-40 minutes. After soaking, start decocting. Generally, antiemetic and purgative medicines are boiled and then decocted for about 5 minutes; tonic medicines are boiled and then decocted for 30-60 minutes. Generally, the medicines are decocted twice, and the liquid obtained from the two decoctions is mixed thoroughly and taken in 2-3 times.
Medicines decocted first need to be decocted separately for 20-30 minutes before they are decocted together with other medicines; medicines decocted later need to be put in after other medicines have been boiled for 10-20 minutes.
The decoction of Chinese medicines requires professional guidance. If you do not have experience in decocting medicines, it is best to have a medical institution to decoct on your behalf.