Herbs that transform Phlegm are able to treat Phlegm syndrome. Phlegm is a kind of pathological product and it is also a secondary pathogenic factor, which will lead to further pathological changes in the body. Dysfunction of the Lung, Spleen, Kidney and San Jiao can result in accumulation of water. Meanwhile, in pathological conditions, Cold can condense water, Heat can consume water, and stagnation of Qi can obstruct the flow of water. Furthermore, the accumulated water becomes a kind of thick, sticky substance that is called ‘Phlegm’. Phlegm interferes with the normal flow of Qi and is also pushed by the Qi to spread through the body, so it may affect all parts of the body, with various manifestations.

Visible phlegm is often seen in clinical practice to accumulate in the Lung, and this can be expectorated. Coughing, wheezing and fullness or stifling feelings in the chest often exist because the Lung-Qi is obstructed.

There is also another kind of Phlegm that is neither visible nor able to be expectorated. This is the so-called ‘invisible Phlegm’. It can result in different symptoms when it stays in different parts of the body. When it accumulates in the Stomach, it may cause nausea, vomiting, loss of appetite, and fullness or distension in the upper abdomen. If it is pushed by rebellious rising Qi, then it moves upwards and disturbs the sensory orifices, and the patient experiences dizziness, vertigo, tinnitus and heavy sensations in the head. If the Phlegm obstructs the Heart and disturbs the Mind, it will cause palpitations, restlessness, insomnia, depression, mental confusion, delirium, mania, coma, Wind-stroke and epilepsy. If it obstructs the meridians and collaterals, and blocks the circulation of the Qi and Blood, then corresponding symptoms may occur in the locality. If in the chest, then chest pain and palpitations may be present; if on the face, there may be distortion of the mouth and the eyes; if in the limbs or the trunk, there will be sensations of numbness and heaviness. If Phlegm accumulates for a long period of time and is combined with other pathogenic factors, it can form masses, such as different kinds of tumor.

The most commonly used substances that transform Phlegm may remove visible Phlegm and are also able to disperse the Lung-Qi and direct it downwards; therefore they can stop coughing. Some of the substances are also able to remove invisible Phlegm; however, since the cause of invisible Phlegm is more complicated, in clinical practice they must be used together with other herbs that regulate the Qi, tonify the Spleen-Qi and transform Dampness to increase the therapeutic effects.

Herbs that transform Phlegm are used to treat Phlegm syndromes, which are caused by visible Phlegm and invisible Phlegm. These substances have the following characteristics.

Xin Ren and Jie Geng both enter the Qi level of the Lung meridian. Both are able to transform Phlegm from the Lung and stop coughing. In clinical practice, they are often used together to treat cold infections and bronchitis. With some other herbs, they can also treat pneumonia, asthma and pulmonary emphysema. However, these two herbs have their own characteristics and they carry out their functions by different methods.

Xing Ren is bitter, warm and slightly poisonous. The bitter taste gives Xing Ren a descending property. Warmth can disperse the accumulation of Phlegm and the stagnation of Qi. It is a kind of seed and it contains oil, which gives this herb a moist nature. The function of Xing Ren is characterized as descending the Lung-Qi and transforming Phlegm in order to stop coughing. It is particularly useful for treating cough with a large amount of Phlegm, fullness in the chest, shortness of breath and nasal obstruction when exterior pathogenic factors invade the Lung and the Lung-Qi fails to descend.

Jie Geng is pungent, bitter and neutral. It is able to transform Phlegm and stop coughing. The pungent and bitter tastes give Jie Geng dispersing and dissipating capacities. It is light both in weight and in nature; therefore its function is characterized as lifting the Lung-Qi gently but sufficiently. It is suitable for treating cough with Phlegm, stifling in the chest and nasal obstruction due to obstruction of the Lung-Qi.

Comparing Jie Geng and Xin Ren, one moves upwards, the other moves downwards; one disperses the Lung-Qi and the other directs the Lung-Qi to descend. They perfectly match each other to regulate the Lung-Qi, eliminate Phlegm and relieve cough. This is why they are often used together in clinical practice.

Jie Geng is bitter, pungent and neutral and enters the Lung meridian. It is light in nature and its function is characterized as ascending and dispersing the Lung-Qi. This feature gives Jie Geng not only the capability of dispersing the Lung-Qi so as to treat cough with Phlegm, but also the possibility of activating the Qi movement in the whole body in order to treat disorders of other organs and meridians. For instance, to treat constipation, or difficult bowel movement due to Qi stagnation in the intestine, besides using purging and descending herbs to stimulate the intestines and promote bowel movement, Jie Geng could also be used to lift the Lung-Qi so as to activate the Qi movement in the Large Intestine because the Lung and Large Intestine are Internally–Externally related. This combination is more effective than if only the descending herbs are used.

Another example is the treatment of difficult urination and edema due to water accumulation in the Lower or Middle Jiao. Besides using herbs that drain water and reduce water accumulation, Jie Geng could be used to disperse the Lung-Qi and open the Upper Jiao so as to accelerate the Qi and water movement in the Middle Jiao and Lower Jiao. The therapeutic result of this combination is also much better than if draining and reducing herbs are used alone. Since Jie Gen is a special herb for regulating the Qi through opening and lifting the Lung-Qi, it is described in the classics as ‘the oar of the boat’, which means that Jie Geng may assist the Qi movement in the opposite direction so as to break up various obstructions.

Because Jie Geng is light and ascending in nature and enters the Lung meridian, it is also very often used as a guide to enter the Lung meridian for herbs that do not enter this meridian. For example, in chronic diarrhea due to Spleen-Qi deficiency, patients may also have shortness of breath and weak voice due to Lung-Qi deficiency, and herbs that tonify the Spleen-Qi can easily enter the Lung as well to tonify the Lung-Qi if Jie Geng is used as a guide.

Bai Qian and Qian Hu are often prescribed as ‘ Er Qian’, meaning ‘the two Qian’, which suggests that these two herbs are often used together. Both are pungent and enter the Lung meridian and are effective for relieving cough. The pungent property gives them the capability of dispersing the Lung-Qi. Meanwhile, the direction of their action is downward; they can effectively descend the Lung-Qi and relieve cough. Both are used for treating fullness in the chest, productive cough and wheezing due to obstruction of the Lung-Qi. They can also be used to treat External syndrome because they are pungent and are able to expel Wind. However, there are some differences between these two herbs, so they can also be used separately in different conditions.

Bai Qian is a warm herb and its action of descending the Lung-Qi is stronger than that of Qian Hu. It is suitable for treating cough, wheezing, asthma and white sputum, which is difficult to expectorate and causes stifling feelings in the chest. Qian Hu is cold in nature and is more suitable for clearing Heat in the Lung and treating cough with green and thick sputum, a sense of constriction in the chest and irritability.

These three herbs all enter the Lung meridian. They have a similar function in moistening the Lung, descending the Lung-Qi, transforming Phlegm and relieving cough. All are warm, pungent and bitter, but they have no drying property and can be used for treating many kinds of cough caused by Exterior or Interior pathogenic factors. They treat cough either in the acute stage or in chronic stages, in Excess or Deficiency syndromes, and in Hot or Cold syndromes. Because of these characteristics, they are widely used in clinical practice. They are often used together to treat bronchitis, pneumonia, upper respiratory tract infection and pertussis.

However, comparing the functions of the three herbs, Zi Wan is the strongest one for transforming Phlegm, Kuan Dong Hua is the most effective one for relieving cough and Bai Bu is the most commonly used to treat chronic cough.

Chuan Bei Mu and Zhe Bei Mu are bitter and cold, and enter the Lung and Heart meridians. Both can transform Phlegm-Heat, dissipate nodules and treat cough with thick, green sputum that is difficult to expectorate, with dryness in the mouth and nasal cavity. However, they also have their own characteristics.