There is a big difference between Si Reverse Tang and Si Reverse San in terms of drug composition, efficacy and clinical application. Si Reverse Tang is a formula to restore yang and save the body from fainting and unconsciousness by warming and tonifying yang qi, while Si Reverse San is a formula to harmonize the liver and the spleen, which is a big difference between the two. Si-Reversing Tang is mainly composed of epiphyllum, dry ginger and licorice, which has the effect of restoring yang and saving reversal. It can be clinically used to treat Shaoyin disease (the disease caused by the invasion of the Shaoyin meridian by an exogenous pathogen), and cold syncope caused by yang deficiency of the heart and kidney. This formula is contraindicated in cases of true heat and false cold. Four Reversible San is mainly composed of Chai Hu, Paeonia lactiflora, Citrus aurantium dulcis and Glycyrrhiza glabra, which has the efficacy of dispelling evils and relieving depression, dredging the liver and regulating the spleen, and it can be clinically used in treating liver and spleen disharmony and yang depression and syncope (the poor functioning of yang qi leading to cold limbs). The clinical difference between Si Reverse San and Si Reverse Tang is large, but because of the similarity of the name, it is easy to be confused, so it is important to distinguish between the two, and should be treated by a professional physician to avoid the mistake of the condition.