In Traditional Chinese Medicine (TCM), Suan Zao Ren 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 Suan Zao Ren is Neutral in nature. This means that Suan Zao Ren 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 Suan Zao Ren means that you don't have to worry about that!
Suan Zao Ren also tastes Sour 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. Sour ingredients like Suan Zao Ren helps with digestion and restrain abnormal discharges of Fluids from the body, such as diarrhea or heavy sweating. 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 Suan Zao Ren is thought to target the Gallbladder, the Heart and the Liver. 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 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.