Actually, phlegm is the best feedback from the lungs! Don't underestimate phlegm—it's the lungs signaling to us. Whether the lungs are comfortable or not can be roughly guessed by looking at the appearance of the phlegm.

First, lung heat—yellow phlegm.

When sputum turns yellow and even becomes somewhat lumpy, you might wonder if it is caused by lung heat. In this case, a person often feels dry mouth and throat, a sore throat that makes speaking difficult, dry mouth and thirst, a rush of hot air upward when breathing, flushed face and red eyes, dry stools, yellow urine, a yellow and greasy tongue coating, and so on. This is because excessive heat in the lungs scorches the body fluids, causing the sputum to become yellow and sticky. At this point, it is necessary to clear and drain lung heat. Adjustments can be made by using Ma Xing Shi Gan Tang (Ephedra, Apricot Kernel, Gypsum, and Licorice Decoction).

Next, Lung Cold – White Sputum

If you are always coughing up thin, clear white sputum, sometimes with a bit of foam, and the amount is not small, then you should be cautious. This is likely caused by lung cold. In such cases, a person is particularly afraid of cold, coughing worsens with the slightest breeze, the back always feels chilly, and the tongue tends to be pale. This is because cold invades the lungs, impairing their normal function, which disrupts the circulation of body fluids and gradually condenses into phlegm. To address this, it is necessary to expel cold and resolve phlegm. Adjustments can be made by using Xiao Qing Long Tang (Minor Green Dragon Decoction).

Finally, Lung Dryness – Sticky Sputum

In people with this condition, there isn’t much phlegm, but it's sticky and gooey, and no matter how much they cough, they can’t clear it all—it always feels like something is stuck in the throat. Not only is the throat uncomfortable, but the mouth, nose, and lips are also extremely dry, and drinking water doesn’t relieve the thirst. The skin feels rough to the touch, coughing produces little phlegm, and the tongue body appears red. This is due to excessive dryness in the lungs—the body fluids have been depleted by pathogenic dryness, making the phlegm both sticky and scant. In this case, it’s necessary to moisturize the lungs and promote fluid production, and one might consider using a modified version of the *Shashen Maidong Tang* (Glehnia and Ophiopogon Decoction) for regulation.

The content of this article is for reference only. Each person’s condition is different. The formulas mentioned above should ideally be reviewed by a professional TCM practitioner and adjusted according to the specific circumstances to ensure safety and effectiveness.