In Traditional Chinese Medicine (TCM), She Gan belongs to the 'Herbs that clear Heat and relieve Toxicity' 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 clear Heat and relieve Toxicity treat the latter while, at the same time, removing infectious toxins from the body. As such they tend to be Cold or Neutral in nature.
As suggested by its category She Gan is Cold in nature. This means that She Gan typically helps people who have too much 'Heat' in their body. 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 She Gan can help restore a harmonious balance between Yin and Yang.
She Gan also tastes Bitter. 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 She Gan tends to have a cleansing action on the body by clearing Heat, drying Dampness and promoting elimination via urination or bowel movements.
The tastes of ingredients in TCM also determine what Organs and Meridians they target. As such She Gan is thought to target the Lung. In addition to performing respiration, the Lungs are thought in TCM to be a key part of the production chain for Qi and the Body Fluids that nourish the body.