In traditional Chinese medicine (TCM)

a herb is often processed before it is used in clinic. The quality of the herb is thus heavily affected by how it is processed. ‘Perspiration’is an on-site processing method that has been used widely. This study reviews not only the origin of the perspiration but also the effect of the perspiration on herb quality

including water content

chemical ingredient composition

pharmacological effect and toxicity. It's suggested that during the perspiration

some enzymes could be activated or deactivated

which resulting in the changes of herb color and chemical ingredients.