Four Reversible San is available in Chinese herbal formulas and proprietary Chinese medicines, and proprietary Chinese medicines are from Chinese herbal formulas. The formula and dosage of Four Reversible San, for example, is 6 grams each of licorice (sizzling), Chaihu, Citrus aurantium dulcis (broken, impregnated with water, sizzling and drying), and Paeonia lactiflora.
Four Reversible San is from “The Treatise on Typhoid Fever”. In the formula, licorice eases the urgency and relieves pain (relieving urgent pain symptoms) and harmonizes the medicinal properties of the medicine, Chai Hu detoxifies the liver and relieves depression, Citrus aurantium breaks down the qi and eliminates accumulation of food (breaking down qi stagnation and eliminating accumulation of food), and Paeoniae lactiflora pacifies the liver and yang.
Four Reversing Powder is used to treat Yang depression and syncope (cold limbs due to poor circulation of Yang qi), manifesting as abdominal pain or lack of warmth in the hands and feet, or discharge and heaviness in the lower part of the body, or dystocia (pain in the area of dorsal and rib cage) in the epigastric region (abdomen), or coughing, or palpitation of the heart or tightness of the dorsal rib cage; and Liver Spleen-Qi Depression manifesting as distension of the dorsal rib cage and tightness of the epigastric region, pain in the epigastric region, and stringy pulse.
The adverse reactions and contraindications of Siwei San are not clear. If there is a need to use Si-Yi San, it should be applied under the guidance of a traditional Chinese medicine practitioner, and should not be taken on its own.