A formula designed to relieve nasal congestion, sinus pressure, and thick yellow nasal discharge caused by a combination of external Wind-Cold trapping the surface and Damp-Heat accumulating internally. It works by releasing the exterior, clearing interior Heat, draining Dampness, and opening the nasal passages.

Qing Bi Tang addresses a complex pattern where an external Wind-Cold invasion coexists with interior Damp-Heat lodged in the nasal passages. The disease logic unfolds in two layers. First, Wind-Cold attacks the body's surface, causing the Lung's dispersing function to falter. When the Lung cannot properly spread its Qi, the nasal passages lose their ventilation and become congested. Second, Heat and Dampness accumulate internally, often because the lingering pathogen transforms into Heat over time, or because pre-existing Dampness and Heat were already present before the Wind invasion.

When Damp-Heat brews in the Lung and Yangming (Stomach) channels, it rises upward along these pathways toward the nose and sinuses, where it congeals into thick, yellow, foul-smelling nasal discharge. The Dampness makes the discharge sticky and difficult to expel, while the Heat gives it a yellow color and may cause local swelling or pain. This explains the characteristic presentation: nasal blockage with yellow sticky mucus, reduced sense of smell, sinus headache, and sometimes fatigue from the Dampness weighing the body down.

The formula works because it addresses both layers simultaneously. It releases the Exterior to restore the Lung's dispersing function, while also clearing interior Heat and draining Dampness to resolve the root cause of the nasal congestion. Without addressing both layers, treating only the Exterior would leave the Damp-Heat festering inside, while clearing only the interior Heat would leave the pathogen trapped at the surface.