If the liver is malnourished premenstrually, the liver's function of coursing and discharging may be impaired, thus leading to or aggravating liver depression qi stagnation. If such a liver-spleen disharmony is not too serious, it commonly causes constipation with slow or difficult defecation, but not necessarily hard, dry stools. When this disharmony becomes more severe just before or at the onset of menstruation, such constipation commonly swings to loose stools or diarrhea. In addition, dampness tends to accumulate in the lower burner during the premenstruum. The blood is sent down to the uterus by the heart via the bao mai.
Blood is thicker than fluids.
Therefore, fluids tend to arrive in the lower burner before the blood. Dampness then obstructs the free flow of yang qi, and thus damp depression may transform into damp heat. The overwhelming majority of Chinese authors recommend Tong Xie Yao Fang as the guiding prescription for IBS of the spastic colon type. However, when complicated by damp heat, this must be modified by various additions and subtractions. When these three formulas are combined, they form an especially good combination for the majority of Western IBS sufferers.