In Traditional Chinese Medicine (TCM), Huang Lian belongs to the 'Herbs that clear Heat and dry Dampness' 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 dry Dampness treat the latter while, at the same time, relieving the body of excess Dampness. As such they tend to be Cold or Neutral in nature.
As suggested by its category Huang Lian is Cold in nature. This means that Huang Lian 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 Huang Lian can help restore a harmonious balance between Yin and Yang.
Huang Lian 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 Huang Lian 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 Huang Lian is thought to target the Gallbladder, the Heart, the Large intestine, the Liver, the Spleen and the Stomach. Similar to modern medicine, in TCM the Gallbladder stores and releases bile produced by the Liver. It also controls the emotion of decisiveness. In addition to regulating Blood flow, the Heart is believed to be the store of the 'Mind' which basically refers to someone's vitality. 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. 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. The Spleen assists with digestion, Blood coagulation and Fluids metabolism in the body. The Stomach is responsible for receiving and ripening ingested food and fluids. It is also tasked with descending the digested elements downwards to the Small Intestine.