This formula was first recorded in the 'Treatise on Cold-induced Diseases' (shang han lun), by Zhang Zhong-jing (circa 150 ‐ 219 C.E.). It was originally used in the treatment of the lesser Yang syndrome (shao yang bing zheng) in acute febrile diseases due to invasion by exogenous Cold. The Cold pathogen has transformed to Heat and is at a level that is midway between the Exterior and the Interior, manifesting with alternating chills and fever, etc.

Zhang recognised that this formula had a broad range of applications, and over the centuries Chinese physicians have found many more. The skilful combination of warming and cooling, as well as tonifying and dispersing ingredients lend this formula it's unique and wide ranging therapeutic applications. Essentially the formula's uses fall into two categories:

• Lesser Yang syndrome of a Cold-induced disease (often seen as complication of the common cold or influenza)
  
• Gallbladder Qi invasion of the Stomach.

The clinical features of each are listed under 'Signs and Symptoms' 1 & 2, respectively.

The formula's actions and indications under the first category have been expanded to include conditions with the essential common clinical feature of alternating sensations of cold and heat, regardless of whether or not they occur in the course of a febrile illness. Thus it may be used as a foundation formula in the treatment of perimenopausal syndrome with hot flushes alternating with cold intolerance. Another common use for this formula is in the treatment of post-viral debility, frequently seen in cases of newly diagnosed chronic fatigue syndrome. Such cases often present with a latent pathogen at the lesser Yang stage (midway between the Exterior and the Interior). This manifests with fatigue and lethargy together with signs of lingering (i.e. subacute) infection: enlarged lymph nodes (principally in the neck and/or groin) with intermittent fever (which may be as subtle as night sweating) as well as increased sensitivity to the cold (hence the presence of alternating heat and cold). Such patients tend to worsen when given tonifying formulas, as such treatments tend to reactivate the pathogen.

The second category includes a broad range of disorders characterised by stagnation of the Liver/Gallbladder Qi which then invades the Stomach. This may arise due to a variety of causes, including prolonged retention of pathogens and intense or prolonged emotional strain. The characteristic clinical features centre on disorder of the both the Liver/Gallbladder (irritability, wiry pulse, etc.) and also the Stomach (nausea, vomiting, etc.).

TCM ACTIONS
Releases the Exterior and disperses Heat; harmonizes and releases lesser Yang (shao yang) stage disorders, soothes the Liver and harmonises the Stomach.

TCM SYNDROMES

• Lesser Yang (shao yang) stage pathogen
  
• Gallbladder Qi invasion of the Stomach

INDICATIONS
Common cold or influenza with lingering low grade fever, chronic fatigue syndrome, post viral debility, bronchitis, tonsillitis, otitis media, cholecystitis, gastritis, duodenitis, hepatitis, puerperal fever, acute sinusitis, perimenopausal syndrome.

SIGNS & SYMPTOMS
(Key clinical features in bold)

• 1. Alternating episodes of fever and chills
  
• Distending pain over the chest and hypochondrium
  
• Bitter taste in the mouth
  
• Swollen lymph nodes
  
• Dry throat
  
• Dizziness
  
• Normal tongue with a thin white coat
  
• Wiry pulse
  
• 2. Irritability
  
• Heartburn
  
• Nausea or vomiting
  
• Poor appetite
  
• Normal tongue with a thin white coat
  
• Wiry pulse