2. Si Nisi Tang-Based Formulas

2. Si Nisi Tang-Based Formulas

The representative formula Si Nisi Tang is the primary remedy for harmonizing the liver and spleen and balancing the inside and outside, composed of bupleurum, zhishi, white peony, and licorice—four herbs in total. According to the "Shanghan Lun," this formula treats "Shaoyin disease, four extremities, where the person may cough, palpitate, have difficulty urinating, abdominal pain, or severe diarrhea." This indicates that the formula can treat cold extremities caused by diseases affecting all systems of the body. Later physicians, through clinical practice, concluded that the aforementioned indications can be summarized as balancing the inside and outside, aiming to harmonize yin and yang between the two, thereby alleviating cold extremities. From a modern medical perspective, this condition is mostly caused by autonomic nervous system dysfunction leading to cold hands and feet, which can be triggered by diseases affecting all systems of the body. In addition, Si Nisi Tang can also harmonize the liver and spleen. Harmonizing the liver and spleen means treating liver-stomach disharmony. The essence of liver-stomach disharmony is that liver wood overpowers earth, clinically manifesting as bitter taste in the mouth, dry throat, irritability, chest and flank discomfort, unwillingness to eat, and abdominal bloating. From a modern medical perspective, this formula can treat chronic stomach diseases and chronic liver diseases. Si Nisi Tang plus fragrant grass and chuan xiong becomes Bupleurum Liver-Soothing Decoction, the preferred remedy for liver qi stagnation and flank pain, suitable for all liver-related pain. Removing zhishi and white peony and adding angelica, polygonatum, safflower, pangolin, da huang, and peach kernel becomes Fu Yuan Huo Xue Tang, an effective formula for treating blood stasis and flank pain, suitable for all traumatic flank pain and costochondritis.