When it comes to "internal heat" (Shanghuo), most people consider it a common occurrence. However, if you do not know the source of the "fire," it is difficult to extinguish. In Traditional Chinese Medicine (TCM), the source can be identified through phlegm, urine, and facial complexion. Today, I will share these three scenarios with you.

First, yellow phlegm indicates Lung Fire. Traditional Chinese Medicine (TCM) posits that the Spleen is the source of phlegm production, while the Lungs are the reservoir for phlegm storage. Phlegm is produced when the Spleen and Stomach fail to transport and transform fluids, leading to internal fluid retention over time. If it remains in the Lungs, the phlegm formed is white or colorless. However, if Lung Fire is exuberant and continuously "heats" this phlegm, it becomes increasingly yellow. This is often accompanied by symptoms such as cough, sore and swollen throat, pain, dry mouth, and dry nose. In such cases, it is necessary to clear and drain Lung Heat.

Next, yellow urine indicates Heart Fire. TCM holds that the Heart and Small Intestine share an interior-exterior relationship. If Heart Fire is too exuberant and shifts downward to the Small Intestine, it causes excessive heat in the Small Intestine Meridian, resulting in yellow urine. Furthermore, as the Heart opens into the tongue, individuals with exuberant Heart Fire are prone to mouth and tongue sores, oral ulcers, and irritability leading to insomnia at night. In these instances, it is necessary to clear the Heart and drain Fire.

Finally, a yellow complexion indicates Liver Fire. This yellowness differs from the sallow complexion associated with malnutrition; it resembles the color of an orange peel. TCM considers the Liver and Gallbladder to have an interior-exterior relationship. If Liver Fire is excessive, it affects the dredging and discharging of bile. When bile "steams" the skin and muscles, it leads to yellowing of the skin; in some cases, even the sclera (whites of the eyes) may appear yellow.

Do you understand now?