In Traditional Chinese Medicine (TCM), Mu Dan Pi belongs to the 'Herbs that cool the Blood' category. Herbs in this category are used to clear inflammatory and infectious conditions, referred to as 'Internal Heat' in TCM. This is why most of the herbs in this category will have both antibacterial and antiviral properties. In TCM one has too much 'Internal Heat' in their body as a result of a deficiency of 'Yin' (which is Cold in nature, see our explanation on Yin and Yang) or, more commonly, an Excess of Yang (Hot in nature). Herbs that cool the Blood treat the latter and as such tend to be Cold or Neutral in nature.
As suggested by its category Mu Dan Pi is Cool in nature. This means that Mu Dan Pi tends to help people who have too much 'Heat' in their body, although with less effect than a plant that would be Cold in nature. Balance between Yin and Yang is a key health concept in TCM. Those who have too much Heat in their body are said to either have a Yang Excess (because Yang is Hot in nature) or a Yin deficiency (Yin is Cold in Nature). Depending on your condition Mu Dan Pi can help restore a harmonious balance between Yin and Yang.
Mu Dan Pi also tastes Bitter and Pungent. The so-called 'Five Phases' theory in Chinese Medicine states that the taste of TCM ingredients is a key determinant of their action in the body. Bitter ingredients like Mu Dan Pi tends to have a cleansing action on the body by clearing Heat, drying Dampness and promoting elimination via urination or bowel movements. On the other hand Pungent ingredients tend to promote the circulations of Qi and Body Fluids. That's why for instance someone tends to sweat a lot when they eat spicy/pungent food.
The tastes of ingredients in TCM also determine what Organs and Meridians they target. As such Mu Dan Pi is thought to target the Heart, the Kidney and the Liver. In addition to regulating Blood flow, in TCM the Heart is believed to be the store of the 'Mind' which basically refers to someone's vitality. The Kidneys do not only regulate the urinary system but also play a key role in the reproductive system and the growth and aging process of the body. The Liver is often referred as the body's "general" because it is in charge of regulating the movements of Qi and the Body Fluids. It also takes a leading role in balancing our emotions.