Si Mo Tang is used to treat the syndrome of Liver-Qi stagnation (poor transportation of Qi and blood in the liver and emotional depression), which is characterized by shortness of breath in the upper air, distension of the chest and diaphragm, plagued fullness under the heart (mainly referring to the distension of the stomach and discomfort) and loss of appetite. Si Mo Tang is composed of ginseng, black cohosh, betel nut and sedum. It has the effects of moving Qi and lowering rebellious Qi (promoting the downward movement of upward rebellious Qi), relaxing the chest and dispersing knots (relaxing the knotted Qi in the chest), and tonifying Qi to support righteousness. In this formula, Wu Yao is pungent, warm and fragrant, which can dredge liver qi stagnation (liver qi is not flowing smoothly) and move the stagnant qi in the spleen and stomach; Shen Xiang is pungent and dispersing, which can move down qi and lower the rebellious qi; Betel nut is hard to bring down and excrete, which breaks the qi leading to lowering qi and lowering the rebellious qi and removing the distension and fullness; and ginseng is beneficial to qi and helps to promote uprightness, which makes it possible to open up the stagnation and move the qi without hurting the upright qi. The combination of all the medicines together can help lowering rebellious Qi, relaxing the chest and dispersing knots, and tonifying Qi to support the positive effect. The adverse effects of this formula are not clear, but it is contraindicated in pregnant women. This formula should be taken under the guidance of traditional Chinese medicine practitioners and reasonably selected according to one’s own situation, do not blindly self-medication.