whilst white, very watery and frothy sputum indicates Phlegm-Fluids.

Differentiation and Treatment

As mentioned above, we shall classify coughs into acute or chronic. Acute cases are usually
characterized by Fullness, while chronic cases may be of the Full or Empty type. Fullness and
Emptiness, however, often combine. Zhang Jing Yue says in the "Complete Book of Jing Yue"
(1634):

Coughs of external origin are very frequent [and are characterized by] some

Deficiency within the Fullness, hence one must tonify somewhat as well as

expelling [pathogenic factors]. In coughs of internal origin there is some Fullness

within Emptiness, hence one must clear and moisten simultaneously.10(161)

Acute Phase

By acute is meant a cough of a few days' or, at most, a few weeks' duration. The most important
fact to establish when seeing a patient suffering from acute cough is whether the cough is
external or internal. All acute coughs are originally due to invasion of external Wind but the
external pathogenic factor may become internal in only a few days while the cough is still at the
acute stage.

The differentiation of patterns according to the 4 Levels provides the clinical framework for the
symptomatology of invasions of external Wind turning into interior Heat. For example, within
the 4 Levels patterns, invasion of Wind-Heat may cause a cough (together with shivering, fever,
aversion to cold, body aches and a Floating-Rapid pulse). If Wind-Heat penetrates into the
Interior it gives rise to the pattern of Lung-Heat with a barking cough (together with high fever,
thirst, sweating, and a Big pulse). Within the 6 Stages patterns, although a change from
Wind-Cold to interior Lung-Heat is not contemplated, it does happen in practice. Thus, acute
Lung-Heat with cough in the course of a febrile disease may derive either from Wind-Heat or
Wind-Cold, although the former is more likely.

Thus, when presented with a patient with acute cough, the crucial distinction must be made
between exterior or interior cough. Apart from many other symptoms, this differentiation may be
made very simply on the basis of the patient's feelings of cold or heat. If the patient shivers and
feels aversion to cold, and this feeling is not alleviated by wrapping up, it indicates an exterior
pattern, i.e. the pathogenic factor is still on the Exterior.

If the patient feels aversion to heat and is generally hot, very thirsty and restless, it indicates an
interior pattern of Heat, i.e. the pathogenic factor is in the Interior and it has turned into Heat.
The presence of cough, breathlessness, some chest pain and possibly flaring of the alae nasi