In Traditional Chinese Medicine (TCM), Fei Zi belongs to the 'Herbs that expel parasites' category. Herbs in this category are used to treat roundworms, tapeworm, hookworm and other intestinal parasites. In most cases, these herbs should be combined with other herbs to assist their action such as 'Purgative herbs that drain downward' or Qi tonics. Typically these herbs should only be prescribed for a short period as they often have some level of toxicity.

Furthermore Fei Zi is Neutral in nature. This means that Fei Zi typically doesn't affect the balance in your body. Balance between Yin and Yang is a key health concept in TCM. Eating too many "Hot" (Yang) ingredients can lead to an imbalance whereby one has a Yang Excess. The inverse is true as well: too many "Cold" (Yin) ingredients can lead to a Yin Excess. The Neutral nature of Fei Zi means that you don't have to worry about that!

Fei Zi also tastes 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. Sweet ingredients like Fei Zi tends 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 Fei Zi is thought to target the Large intestine, the Lung and the Stomach. 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. 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. 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.