Transforms Dampness and harmonizes the Middle Jiao
Promotes urination and reduces edema
Secondary Actions
Induces mild sweating for summer exterior patterns without sweating
Calms nausea, vomiting, and diarrhea from summer Damp-Cold
Classic Formulas
Xiang Ru San (香薷散) — Xiang Ru with Bai Bian Dou and Hou Po; classic formula for summer-cold exterior pattern with chills, fever, headache, and absence of sweating
Xin Jia Xiang Ru Yin (新加香薷饮) — updated Qing dynasty formula adding Lian Qiao and Jin Yin Hua; treats summer-heat with concurrent wind-cold exterior and interior dampness
Classical References
Ben Cao Gang Mu (Li Shizhen): 'Xiang Ru is the Ma Huang of summer — it releases the exterior through diaphoresis but acts specifically on Summer-Heat patterns'
Described as essential in summer as ephedra is in winter; critical distinction: must be taken cool — hot decoction causes vomiting
Modern Research
Active Compounds
Rosmarinic acid (predominant phenolic; highest in flowers)
Chlorogenic acid
Luteolin-7-O-glucoside (antiviral flavonoid)
Rutin
Thymol (essential oil component; antibacterial)
Carvacrol (essential oil; antibacterial)
p-Cymene
Studied Effects
Anti-inflammatory and antioxidant: ethanolic extracts show significant reduction in NO production and free-radical scavenging; rosmarinic acid and chlorogenic acid are principal active phenolics across all plant parts (PMID 32150805)
Antiviral: luteolin-7-O-glucoside inhibits Human Coronavirus OC43 replication with IC50 ~2 µM, approximately 2.5-fold more potent than the whole ethanol extract (IC50 ~5 µg/mL); supports traditional use in summer respiratory infections
Antibacterial: essential oil components thymol and carvacrol show inhibitory activity against Staphylococcus aureus, MRSA, and Escherichia coli