Some people always wash traditional Chinese medicine (TCM) before decocting it with clean water, thinking that it can ensure hygiene. However, this is incorrect. TCM herbs undergo a series of processing steps, including impurity removal and drying, before being made into medicinal slices. The hygiene conditions are already up to standard, so there is no need to wash them with water. There are several reasons why TCM should not be washed before decocting:
Washing with water can cause the loss of water-soluble components in the herbs. Many herbs contain water-soluble sugars and glycosides. After washing, these active ingredients will partially dissolve in the water and be lost, leading to a decrease in medicinal efficacy and affecting the therapeutic effect.
Washing with water can cause the loss of powdered herbs. Many herbs in TCM prescriptions are in powdered form and need to be ground during dispensing, such as Longgu (fossil bone), Muli (oyster shell), Huashi Fen (talcum powder), and Taoren (peach kernel). If they are washed with water, it will inevitably lead to the loss of these medicinal substances, affecting the therapeutic effect.
Washing with water can cause the loss of some auxiliary materials. Some herbs, such as Vinegar-prepared Yuanhu (Rhizoma Corydalis), Honey-fried Mahuang (Herba Ephedrae), Wine-prepared Dahuang (Radix et Rhizoma Rhei), and Gallbladder Xing (Rhizoma Arisaematis) are processed with auxiliary materials such as honey, vinegar, wine, and bile, which are all soluble in water. If washed with water, it will result in the loss of some auxiliary materials.
It is worth mentioning that TCM herbs should be soaked in water before decocting. Most TCM herbs are derived from plants, and many of them contain proteins and starches. If these herbal medicines are immediately decocted without soaking in water, the proteins will coagulate and the starches will gelatinize when heated, which will hinder the extraction of active ingredients. Therefore, before decocting TCM herbs, they should generally be soaked in cold water for 30 minutes to one hour, allowing the water to penetrate the herbs and dissolve some of the active ingredients in the water, so that they can be fully decocted. The amount of water added should generally be controlled to ensure that the herbs are fully submerged and about one centimeter above them.
