Phlegm-fluid

Phlegm-fluid (Tan-yin) is a pathological concept in Traditional Chinese Medicine (TCM) rather than a specific therapeutic target molecule such as a protein or receptor [4, 10]. It denotes the abnormal accumulation and retention of metabolic fluids, typically attributed to the functional impairment of the spleen, lungs, and kidneys in fluid transformation [10, 14]. Clinically, it manifests as thin, clear fluids (tan yin) or thicker mucus (phlegm) associated with conditions like chronic bronchitis, asthma, and Meniere's disease [1, 9, 15]. At a molecular level, this state is linked to the dysregulation of aquaporins (e.g., AQP2), overproduction of mucin glycoproteins (e.g., MUC5AC, MUC5B), and inflammatory signaling pathways such as JAK-STAT [4, 5, 7]. Therapeutic interventions include traditional formulas like Lingguizhugan decoction, which targets lipid and water metabolism [10], and modern mucolytics like N-acetylcysteine that decrease fluid viscosity [7]. Because Phlegm-fluid represents a pathological syndrome rather than a single molecular entity, it is considered an 'incorrect' target in a strictly molecular context but remains a significant focus in integrative pharmacology [4, 11].

Other names

Tan-yinPhlegm-fluid retentionPhlegm-dampnessSputumMucus

Modulation of fluid metabolism via aquaporin regulation (e.g., AQP2), reduction of mucus viscosity through disulfide bond disruption, and inhibition of inflammatory signaling pathways such as JAK-STAT [4, 5, 7, 10].