Introduction: The medication characteristics and treatment methods for cough due to damp-heat obstructing the lung.

Cough caused by damp-heat obstructing the lung has been discussed in the works of physicians throughout history.

Based on clinical observations, cough due to damp-heat obstructing the lung can result from external pathogenic damp-heat attacking the lung, the combination of external dampness with internal heat, damp-heat from the spleen and stomach ascending to affect the lung, or from lung disorders leading to the accumulation of dampness and heat.

The main clinical manifestations include: in addition to rebellious qi and cough, there may be copious thick sputum that is white or slightly yellow, or coughing up frothy sputum, chest tightness and discomfort, thirst with little desire to drink, a sticky sensation in the mouth, poor appetite, heavy and fatigued limbs, scanty dark urine, sticky and difficult-to-pass stools, a tongue coating that is white, greasy, and slightly yellow, and a slippery, rapid pulse.

In new-onset cases caused by damp-heat, the condition is often an excess syndrome, with the main pathological changes located in the lung. At this stage, the focus should be on clearing and resolving damp-heat in the upper jiao.

Although chronic cough often presents with deficiency patterns involving the lung, spleen, and kidney, damp-heat pathogens may also linger and persist.

If the lungs fail to regulate and govern, they cannot regulate the water passages and transport fluids downward to the bladder, leading to the accumulation of dampness and generation of heat; if the spleen fails in transportation and transformation, it gathers dampness, brews heat, and produces phlegm; kidney yin deficiency can generate heat, which may scorch and consume body fluids. All these conditions can lead to deficiency giving rise to excess, subsequently resulting in syndromes of damp-heat and turbid phlegm.

Although coughing is not solely related to the lungs, it is never separate from them. Therefore, even in chronic illnesses, the presence of damp-heat in the upper jiao should not be overlooked.

Thus, for chronic cough, it is essential not only to focus on deficiency of healthy qi but also to consider whether pathogenic damp-heat exists. One must carefully differentiate between deficiency and excess, avoiding the mistake of indiscriminately prescribing tonifying and supplementing formulas for chronic conditions, thereby violating the principle of "treating excess as excess."

Clearing and resolving damp-heat in the upper jiao and diffusing lung qi are important therapeutic principles for treating this syndrome.

In clinical practice, I prefer to use Qianjin Weijing Tang (Thousand-Gold Reed Stem Decoction) with modifications. For cases with obvious phlegm-heat, combine it with Maxing Shigan Tang (Ephedra, Apricot Kernel, Gypsum, and Licorice Decoction), and consider adding Imperatae Rhizoma (Mao Gen), Scutellariae Radix (Huang Qin), Fritillariae Cirrhosae Bulbus (Chuan Bei), and Trichosanthis Fructus (Gua Lou). For excessive dampness and profuse phlegm, with a white greasy tongue coating and no thirst, add Pinelliae Rhizoma (Ban Xia) and Magnoliae Officinalis Cortex (Hou Po). For external constraint by wind-cold, add Perillae Folium (Su Ye) and Peucedani Radix (Qian Hu).

Phragmitis Rhizoma (Wei Jing) is sweet and cold in nature, capable of clearing heat and promoting diuresis. Coicis Semen (Sheng Yi Ren) is sweet, bland, and slightly cold, promoting diuresis and strengthening the spleen to eliminate the source of damp-heat. Scutellariae Radix (Huang Qin) is bitter and cold; bitterness can dry dampness, while coldness can clear heat, making it a key herb for damp-heat in the upper jiao.

For diseases involving both dampness and heat, it is essential to first regulate the flow of qi, ensuring smooth circulation of both qi and water. This allows dampness to transform through water and heat to transform through qi, preventing the congealing of damp-heat. Therefore, when applying the method of clearing heat and dispelling dampness, attention should be paid to the balance of ascending and descending actions in the formula, as well as promoting the diffusion of lung qi.

Commonly used herbs such as Ephedrae Herba (Ma Huang), Armeniacae Semen Amarum (Xing Ren), Perillae Fructus (Su Zi), Perillae Folium (Su Ye), Peucedani Radix (Qian Hu), and Magnoliae Officinalis Cortex (Chuan Po) all have the function of diffusing and descending qi to regulate its flow. When qi circulation is smooth, water-dampness can be eliminated. Once dampness is removed, heat becomes isolated and easier to clear, and coughing naturally subsides.

Since the lungs are delicate organs located in the upper jiao, the choice of medication should favor light and nimble substances, as the saying goes, "Treating the upper jiao is like handling a feather; without lightness, it cannot be lifted." For damp-heat obstructing the lungs, the use of "light and nimble" medications primarily carries three meanings:

First, the aroma and taste are light and mild. Medications with a light aroma can ascend to enter the lungs and dispel damp-heat from the upper jiao. Because the lungs are delicate and intolerant to extreme cold or heat, clearing and transforming damp-heat must be done appropriately. Clearing heat should not be overly bitter and cold, and transforming dampness should not be overly warm and drying. It is essential to avoid the bias of the medication's nature and flavor to prevent harming the lungs.

Second, the medicinal properties are nimble and dynamic. When damp-heat obstructs and lung qi becomes stagnant, leading to coughing, the use of light, nimble, and flowing substances is beneficial for promoting the smooth flow of lung qi.

Third, the medicinal potency is mild. For damp-heat obstructing the lungs, excessive sweating or purging is prohibited. Only mild formulas should be used to clear and transform the damp-heat, while harsh and aggressive remedies are unsuitable.

For chronic cough with lung deficiency, qi-tonifying and yin-nourishing substances are also essential, but the principle should always be to avoid obstructing damp-heat, tonify without causing stagnation, and nourish without inducing greasiness. Commonly used herbs include Radix Pseudostellariae and Radix Glehniae.

Patient Xie, female, 53 years old, initial consultation on October 25, 1984.

Cough recurring for over 10 years. In September of this year, due to a common cold, the cough recurred, accompanied by fever and chills, with phlegm difficult to expectorate. Previously treated at a hospital in Shanghai, body temperature returned to normal, but the cough persisted. Came to Beijing for treatment.

Main symptoms: Severe cough, phlegm rales in the throat, dizziness, chest tightness with poor appetite, dry mouth but not drinking much water, loose stools with difficulty in defecation. Tongue: pale red with thin, yellowish, slightly greasy coating. Pulse: wiry, thin, and slippery. Syndrome pattern: damp-heat obstructing the lungs. Treatment principle: clear and transform damp-heat, diffuse the lungs, and relieve cough.

Prescription: Reed Stem 24g, Cogongrass Rhizome 18g, Apricot Kernel 9g, Pinellia Tuber 9g, Baical Skullcap Root 9g, Snakegourd Fruit 15g, Sichuan Fritillary Bulb 6g, Perilla Fruit 9g, Perilla Leaf 9g, Ephedra 6g, Raw Gypsum 18g, Coastal Glehnia Root 15g, Magnolia Bark 12g, Tangerine Peel 9g, Licorice Root 6g

After taking the above prescription for 5 doses, the cough was alleviated, and the phlegm sound in the throat also decreased. Following the previous method, with slight adjustments to the medication, after taking more than 20 doses, the cough was completely resolved.