Huo Xiang (藿香) — TCM Patchouli for Summer-Damp, Nausea & Vomiting

At a Glance

• Herb: Huo Xiang
• Chinese name: 藿香 (Huò Xiāng)
• Latin name: Pogostemonis Herba
• Nature: Slightly Warm
• Taste: Acrid
• Meridian: Lung / Spleen / Stomach
• Category: Herbs that Transform Dampness
• Introduction: Huo Xiang (Herba Pogostemonis) is the dried aerial part of Pogostemon cablin (Guang Huo Xiang — patchouli, from Guangdong) or Agastache rugosa (Tu Huo Xiang — native giant hyssop), first recorded in the Ming Yi Bie Lu (ca. 500 CE). This pungent and slightly warm herb is the defining herb for Summer-Damp patterns — the classic warm-humid season presentation of simultaneous exterior obstruction and interior Damp accumulation with nausea, vomiting, diarrhea, and headache. Patchoulol and pogostol sesquiterpenes are key active compounds contributing to antiemetic, antimicrobial, and gastroprotective effects in modern research. Huo Xiang Zheng Qi San, the formula built around this herb, remains one of the most widely used patent medicines in China for seasonal gastrointestinal complaints.

Action

• Aromatically transforms Dampness and releases the exterior — primary herb for Summer-Damp
• Harmonizes the Middle Burner and stops vomiting — most important aromatic antiemetic herb
• Stops diarrhea from Damp accumulation in the intestines

Clinical Application

• Summer-Damp exterior pattern — fever with chills, no sweating, headache, nausea, vomiting, chest oppression, and diarrhea
• Vomiting from any Damp etiology — the primary aromatic antiemetic; particularly for nausea with white greasy tongue coat
• Pregnancy nausea and morning sickness with Damp-Cold component
• Diarrhea from Damp-Cold or Summer-Damp accumulation in the intestines

Precautions

• Dose: 5–10 g dried in decoction; fresh herb 15–20 g; add near end of decoction
• Contraindicated in Yin deficiency heat or excess heat patterns without Damp component
• Fresh herb (Xian Huo Xiang) has stronger exterior-releasing action; dried herb focuses more on Middle Burner Damp
• Generally safe including in pregnancy when indicated for nausea from Damp-Cold

Formula

• Huo Xiang Zheng Qi San (藿香正气散) — Huo Xiang + Zi Su Ye + Bai Zhi + Ban Xia + Bai Zhu + Fu Ling + Hou Po + Chen Pi + Da Fu Pi + Jie Geng + Gan Cao, for Summer-Damp with simultaneous exterior and interior Damp — one of China’s most widely used classical formulas
• Combined with Pei Lan for enhanced Summer-Damp clearing with turbidity
• Combined with Huang Lian for Summer-Damp with Heat complication — nausea with yellow tongue coat

Combinations

• Patchouli Herb (藿香) + Atractylodes Rhizome (苍术) + Magnolia Bark (厚朴) → Huo Xiang Zheng Qi San (藿香正气散) core: transform damp, release exterior, summer-damp cold, vomiting and diarrhea
• Patchouli Herb (藿香) + Eupatorium Herb (佩兰) + Lotus Leaf (荷叶) → transform summer-damp, clear turbidity, summer-heat with damp, thick greasy tongue coating
• Patchouli Herb (藿香) + Pinellia Rhizome (半夏) + Aged Tangerine Peel (陈皮) → transform damp-phlegm, stop vomiting, nausea and vomiting from damp
• Patchouli Herb (藿香) + Coptis Rhizome (黄连) + Talc (滑石) → clear damp-heat, stop diarrhea, damp-heat diarrhea with vomiting
• Patchouli Herb (藿香) + Amomum Fruit (砂仁) + Round Cardamom (白豆蔻) → warm and aromatically transform damp, middle jiao damp stagnation with cold

Pharmacological Effects

• Antiemetic
  • patchouli alcohol — inhibits gastric smooth muscle contractions
• Anti-inflammatory; antimicrobial
  • broad spectrum — antibacterial, antifungal, antiviral
• Antifungal
  • effective against Candida and dermatophytes
• Immunomodulatory; antioxidant; antidepressant
  • inhaled — calms nervous system
• Carminative; expectorant
  • mild)
  • 藿香正气散 is the most widely sold OTC TCM formula in China — treats summer-damp cold
  • NOTE: fresh herb (鲜藿香) preferred when available for summer-heat patterns

Classic Description

• Ming Yi Bie Lu: ‘Governs wind-water toxic swelling; eliminates malign qi; heals cholera; heart pain.’
• Ben Cao Tu Jing: ‘For treating spleen-stomach vomiting and counterflow — the most essential medicinal.’
• Ben Cao Gang Mu: ‘Patchouli Herb — for treating spleen-stomach vomiting and counterflow, the most essential medicinal. Ascends and descends all qi; spleen-stomach vomiting and counterflow; cholera, diarrhea, and dysentery; bad breath; eliminates irregular and pathogenic qi.’
• Ben Cao Bei Yao: ‘Pungent, sweet, and mildly warm; enters the hand and foot taiyin; moves qi and harmonizes the middle; opens the appetite and stops vomiting; eliminates malign qi; heals cholera vomiting and diarrhea, heart-abdominal cold pain; disperses exterior pathogenic factors; dispels filth and malign influences; treats mountain miasma and pestilential qi.’