Fortune Eupatorium Herb Classic Formulas

Primary Actions

Aromatically transforms dampness and awakens the Spleen - Pei Lan is used for chest or epigastric oppression, greasy taste, poor appetite, nausea, and summer humidity affecting the middle burner.
Releases early summer-damp or damp-warm patterns - it is chosen for mild fever, headache, chest fullness, and greasy tongue coating when exterior and interior turbidity coexist.
Freshens the mouth and clears stale damp-heat turbidity - traditional use includes halitosis, excessive saliva, and sweet-greasy taste in the mouth from middle-jiao damp obstruction.

Gan Lu Xiao Du Dan - damp-warm epidemic formula lineage in which Pei Lan helps aromatically resolve turbidity from the middle and the exterior.

TCM Wiki describes Pei Lan as pungent and neutral, entering the Spleen, Stomach, and Lung to resolve dampness and release the exterior.
Traditional pairing with Guang Huo Xiang is repeatedly emphasized for damp obstruction of the middle and early summer-damp patterns.
Shen Nong Ben Cao Jing is cited as the early classical source naming Pei Lan.