In Traditional Chinese Medicine (TCM), Fu Shen belongs to the 'Herbs that nourish the Heart and calm the Spirit' category. These herbs are substances that tranquilize the Mind and treat symptoms such as restlessness, palpitations, anxiety or insomnia. They tend to have sedative properties by tonifying Heart Yin and Blood as in TCM it is believed that the Heart is the store of the Mind.
Furthermore Fu Shen is Neutral in nature. This means that Fu Shen 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 Fu Shen means that you don't have to worry about that!
Fu Shen 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 Fu Shen 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 Fu Shen is thought to target the Spleen and the Heart. In TCM the Spleen assists with digestion, Blood coagulation and Fluids metabolism in the body. In addition to regulating Blood flow, the Heart is believed to be the store of the 'Mind' which basically refers to someone's vitality.