Heat (Fire) occurs mostly in summer but is also found in other seasons. From the time of Huangdi Neijing, Heat and Fire have been interchangeable. Fire is the matter, and Heat is the manifestation. Identical physically and pathogenically, they are usually used indistinguishably. The pathogenic Heat (Fire) has the following characteristics:
| (1) | Heat (Fire) is hot, belongs to Yang, and has rising up properties. | |
| • | Therefore Heat (Fire) diseases have the following symptoms: high fever, heat aversion, restlessness, thirst, sweating, and a full rapid pulse. | |
| • | When Heat (Fire) rises to the head, it may disturb the mental state and cause dysphoria, insomnia, mania, coma, and delirium. | |
| • | Yang implies jitteriness and quickness, and therefore Heat (Fire) diseases attack and transmit quickly. | |
| (2) | Heat (Fire), a Yang, consumes Qi and impairs Body Fluid. | |
| • | Extreme Heat reduces Yin to Yin-Fluid sweat. Heat (Fire) diseases have Heat and Body Fluid related symptoms: thirst, desire for fluids, dry throat and tongue, dry stools, and scant dark urine. | |
| • | Huangdi Neijing says, “Strong Heat (Fire) consumes Qi.” Qi is lost as excessive sweat caused by the Heat (Fire). That is why, even after the Heat (Fire) disease is cured, the body still suffers from insufficient Qi, and requires a gradual recovery period. | |
| (3) | Heat (Fire) brings Wind and rouses blood. | |
| • | When Heat (Fire) attacks, it “burns” on the Liver meridian, removes Yin-Fluid nourishment from the tendons and vessels, and stirs up the body’s Liver-Wind. “Extreme Heat (Fire) brings Wind.” The symptoms are epitasis, limb convulsions, coma, delirium, upward-staring eyes, opisthotonus, high fever, and stiff neck. | |
| • | Blood clogs when cooled and moves when warmed. However, if it is too warm, Blood flows too quickly and may damage vessels, and this forces the Blood out of its course. The symptoms are hematemesis, hematochezia, excess menorrhea, abrupt excess uterine bleeding eruptions, and hematuria. | |
| (4) | Heat (Fire) causes swelling and skin infection when it enters Blood, accumulates locally, and damages adjacent muscles. These infections are also known as Heat (Fire)-toxins, and TCM says, “carbuncles and furuncles originate from Fire-toxins.”Heat (Fire) infections have redness, swelling, heat, and pain. | |
