White Penetrating Decoction · bai tong tang

In brief

A formula of three drugs for lesser yin diarrhoea with a faint pulse, where yin cold fills the interior and the yang can no longer hold the lower burner. Fresh scallion stalk, white and pungent, opens the blocked yang in the vessels; dried ginger and raw aconite warm the middle and restore the fire. It is the answer to cold diarrhoea not yet at the point of collapse. Where the diarrhoea will not stop, the limbs are cold and pulseless, and dry retching with vexation appears, the yang is being pushed upward and out; then human urine and pig’s bile are added, their salt and bitterness serving as a counterweight that leads the warming drugs down into the yin. The chapter adds its own test: if the pulse bursts out after the decoction the case is fatal, if it returns faintly and steadily the patient lives.