This formula was first recorded in ‘All Diseases Return to Spring’ (wan bing hui chun) by Gong Ting-xian (a.k.a. Gong Yun-lin), 1587. ‘Return to Spring’ (hui chun) is a poetic expression, still in use today, denoting the restoration of health after an illness – the state of ill health being like the season of Winter. In addition to being a distinguished physician, Gong was renowned for his mastery of tui-na, hence his interest in musculoskeletal disorders, for which this formula was designed.

The name of the formula is literally: ‘Unblock the Channels and activate the Blood formula’. This refers to the focus of this formula’s action on activating the Blood and dispelling stasis, in addition to dispelling Wind-Cold-Damp.

The formula’s therapeutic actions are based on the theory that Blood deficiency predisposes to invasion by Wind, and that pathogenic Wind causes injury to the Blood, setting up a vicious cycle. In addition, the invading Wind generally carries other exogenous pathogens with it, i.e. Cold-Damp. As a consequence of the invasion of the Channels-collaterals, tendons and muscles by Wind, Cold and Damp, the movement of the Qi and Blood becomes obstructed. 

In order to effectively treat such conditions, Blood nourishing herbs need to be included (along with the herbs that dispel static Blood) in order to protect the Blood from the harsh dispersing action of these herbs (i.e. to harmonise the Blood). Moreover, Blood nourishing herbs help to regenerate the health Qi to prevent further invasion and promote the expulsion of the pathogens. Thus, the formula is built on a base of Si Wu Tang (Dang Gui Four Combination), to which are added groups of herbs to dispel Wind-Damp and activate the Blood to dispel stasis.