Natural Herb Library

Japanese St. Johnswort Herb

Chinese
地耳草
Pinyin
Di Er Cao
Latin
Herba Hyperici Japonici
Botanical illustration of Japanese St. Johnswort Herb, Hypericum japonicum, showing habit, leaves, flowers, capsule fruit, seed, root, and diagnostic plant details.
Botanical plate by Kodi . View print →

Known in TCM as Di Er Cao (地耳草), this bitter and sweet, cool herb enters the Lung, Liver, Kidney, and Bladder. Traditionally, it clears Heat and resolves toxicity, most often applied for hepatitis, jaundice, and urinary tract infection. Modern research has identified Quercetin among its active constituents.

Part used: Whole herb

Also Known As

Hyperici

Latin: Herba Hyperici Japonici | Pinyin: Di Er Cao | Chinese: 地耳草

TCM Properties

Taste
bitter, sweet
Temperature
cool
Channels
Lung, Liver, Kidney, Bladder

Traditional Use

Primary Actions

  • Clears Heat and resolves toxicity
  • Promotes urination and treats Damp-Heat jaundice
  • Disperses Blood stasis and reduces swelling
  • Clears Lung Heat … used for cough, hemoptysis, and lung abscess

Secondary Actions

  • Anti-inflammatory for hepatitis and cholecystitis … key clinical use
  • External application for traumatic injury, furuncles, snakebite, and infected wounds

Classical References

  • Also known as Tian Ji Huang (田基黄); commonly used in Lingnan (Guangdong/Guangxi) folk medicine for infectious hepatitis and jaundice
  • Ben Cao Tui Chen: 'Di Er Cao resolves toxicity, cools blood, and promotes urination … applicable to jaundice, dysentery, and sores'
  • Note: Di Er Cao (地耳草, Hypericum japonicum) is NOT the same plant as Guan Ye Lian Qiao (贯叶连翘, Hypericum perforatum, Western St John's Wort) … different species with distinct pharmacology and safety profiles; the Western species carries significant drug interactions (CYP3A4 inducer) that do NOT apply to H. japonicum

Modern Research

Active Compounds

  • Quercetin
  • Quercitrin (quercetin-3-rhamnoside)
  • Isoquercitrin (quercetin-3-glucoside)
  • Kaempferol
  • Tetramethoxyluteolin (5,7,3′,4′-tetramethoxyflavone; hepatoprotective)
  • Hypericin and pseudohypericin (trace levels; much lower than H. perforatum)
  • Chlorogenic acid
  • Xanthones (trace)

Studied Effects

  • Hepatoprotective in cholestatic hepatitis: network pharmacology identified quercetin as a central multi-target node acting on PTGS2 (COX-2), BCL2, CYP7A1, and FXR pathways; molecular docking confirmed direct binding … provides mechanistic basis for classical Damp-Heat jaundice indication (PMID 33657087)
  • Anti-hepatitis B: Di Er Cao extract and isolated flavonoids inhibit HBsAg and HBeAg secretion in HepG2.2.15 cells; tetramethoxyluteolin identified as the most active compound with IC50 comparable to lamivudine in cell assays
  • Anti-inflammatory and antioxidant: total flavonoids reduce LPS-induced NO, IL-6, and TNF-α in RAW264.7 macrophages; DPPH radical scavenging IC50 comparable to ascorbic acid

PubMed References

Safety & Interactions

Contraindications

  • Cold-Damp jaundice or diarrhea (no fever, pale jaundice, cold limbs)
  • Spleen-Stomach Deficiency Cold

Cautions

  • Standard dose 15–60g fresh herb; 15–30g dried in decoction
  • IMPORTANT: Do not confuse with Hypericum perforatum (Western St John's Wort, Guan Ye Lian Qiao 贯叶连翘) … H. perforatum is a potent CYP3A4 inducer with major drug interactions; H. japonicum does NOT share this pharmacology and has a separate safety and interaction profile
  • Hypericin content in H. japonicum is trace-level compared with H. perforatum; photosensitisation risk is negligible at standard oral doses

Conditions

Frequently Asked Questions

What is Japanese St. Johnswort Herb used for?

Japanese St. Johnswort Herb is traditionally used to Clears Heat and resolves toxicity, Promotes urination and treats Damp-Heat jaundice, Disperses Blood stasis and reduces swelling, Clears Lung Heat … used for cough, hemoptysis, and lung abscess. Research has investigated its effects on: Hepatoprotective in cholestatic hepatitis: network pharmacology identified quercetin as a central multi-target node acting on PTGS2 (COX-2), BCL2, CYP7A1, and FXR pathways; molecular docking confirmed direct binding … provides mechanistic basis for classical Damp-Heat jaundice indication (PMID 33657087); Anti-hepatitis B: Di Er Cao extract and isolated flavonoids inhibit HBsAg and HBeAg secretion in HepG2.2.15 cells; tetramethoxyluteolin identified as the most active compound with IC50 comparable to lamivudine in cell assays.

What are other names for Japanese St. Johnswort Herb?

Japanese St. Johnswort Herb is also known as Hyperici. In TCM: 地耳草 (Di Er Cao); Herba Hyperici Japonici.

Is Japanese St. Johnswort Herb safe during pregnancy?

The safety of Japanese St. Johnswort Herb during pregnancy has not been established. Consult a qualified healthcare provider before use.

What are the contraindications for Japanese St. Johnswort Herb?

Japanese St. Johnswort Herb should not be used in: Cold-Damp jaundice or diarrhea (no fever, pale jaundice, cold limbs); Spleen-Stomach Deficiency Cold. Consult a qualified practitioner before use.