Fragrant Solomonseal Rhizome Classic Formulas

Primary Actions

Nourishes Lung Yin and moistens dryness - Yu Zhu is used for dry cough, hoarseness, throat dryness, and scant sputum when dryness or post-febrile injury has depleted fluids.
Nourishes Stomach Yin and generates fluids - it treats thirst, dry mouth, hunger without appetite, and dry stool from Stomach fluid deficiency.
Gently clears residual heat without being cloying - this makes it useful in warm-dryness and post-illness patterns where some exterior or residual heat remains.

Sha Shen Mai Dong Tang - classic dryness-injured Lung formula pairing Yu Zhu with Sha Shen and Mai Men Dong.
Yi Wei Tang - Stomach-Yin formula in which Yu Zhu helps restore fluid and appetite after heat has damaged the middle burner.
Qianjin Weirui Tang - wind-warm and Yin-deficiency exterior formula where Yu Zhu acts as the principal moistening herb.

TCM Wiki describes Yu Zhu as sweet and slightly cold, entering the Lung, Stomach, and Heart to nourish Yin and clear slight heat.
Formula commentary from Qianjin Weirui Tang and Sha Shen Mai Dong Tang emphasizes Yu Zhu's ability to moisten without trapping residual pathogen.