This formula is derived from a combination of Yin Qiao San (Lonicera & Forsythia Formula) and Sang Ju Yin (Mulberry and Chrysanthemum Formula). Both formulas were first recorded in the ‘Analysis of Warm Diseases’ (wen bing tiao bian), by Wu Ju-tong (a.k.a. Wu Tang), 1798. They are designed to treat Defense aspect syndrome (wei fen zheng) due to invasion by Wind-Warm or Wind-Heat.

In contrast to the former, to which it is very similar, the latter formula focuses on relieving coughing by disseminating the Lung Qi. This is mainly achieved by the skilful combination of Platycodon root (jie geng), which has an ascending action, together with Prunus seed (xing ren), which has a descending action. These two herbs, together with Phragmites rhizome (lu gen), free the Lung Qi, which has become obstructed by the invading pathogens.

In clinical practice these two formulas are often combined in order to provide a comprehensive treatment for acute upper respiratory infections. This is particularly important in cases with Wind-Heat as these pathogens give rise to conditions that tend to progress rapidly. In this situation the treatment aims to prevent the pathogens from moving further down the respiratory tract into the Lung, in addition to resolving the Exterior syndrome (i.e. the URTI).

In terms of modern research, the key herbs have the following actions.

• Lonicera flower (jin yin hua): antibacterial, anti-inflammatory, antipyretic and immune stimulant.
• Forsythia fruit (lian qiao): antibacterial, anti-inflammatory.
• Morus leaf (sang ye): antibacterial, hypoglycaemic and antitussive.
• Chrysanthemum flower (ju hua): antibacterial and antitussive
• Traditionally used in Chinese medicine to release Exterior
• Traditionally used in Chinese medicine to remove Heat toxin
• Traditionally used in Chinese medicine to diffuse lung-qi
• Traditionally used in Chinese medicine to expel wind-heat