In Traditional Chinese Medicine (TCM), Fan Xie Ye belongs to the 'Purgative herbs that drain downward' category. The herbs in this category are those whose main purpose is to treat constipation. The fact they're 'purgative' means that they do so by removing Excess Heat in the Intestines and/or Stomach. As such all herbs in this category are Cold in nature, in order to cool the Heat.

Furthermore Fan Xie Ye is Cold in nature. This means that Fan Xie Ye 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 Fan Xie Ye can help restore a harmonious balance between Yin and Yang.

Fan Xie Ye also tastes Bitter and Sweet. 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 Fan Xie Ye 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 Sweet ingredients tend to slow down acute reactions and detoxify the body. They also have a tonic effect because they replenish Qi and Blood.

The tastes of ingredients in TCM also determine what Organs and Meridians they target. As such Fan Xie Ye is thought to target the Large intestine. In TCM the Large Intestine receives the "impure" parts of the digested food from the Small Intestine, absorbs the remaining fluids and excrete the remainder as feces.