In general, it is not recommended to decoct the dregs of Chinese medicine overnight. Because overnight dregs of traditional Chinese medicine, after a night of placing, part of the active ingredients may have been lost, and the drugs inside may be deteriorated, this time again decoction may affect the efficacy of the drug. The correct decoction method is: soak the drug before decoction, which is conducive to the dissolution of active ingredients, but also shorten the time of decoction, generally soak in cold water for 20 to 30 minutes. The decoction is usually first boiled with the fire, and then decocted with the fire for about 1 hour. Generally speaking, Chinese herbal medicines should be decocted twice, and the amount of water added in the second decoction should be 1/3~1/2 of that in the first decoction, and the decoction should be dregs removed, filtered and mixed, and then divided into 2~3 times. The medication should be used under the guidance of a doctor, do not use the medication blindly, so as not to threaten your health. In case of discomfort, please consult a doctor promptly.