Da Qing Ye (Indigo or Woad Leaf)

Chinese Herb Actions

Chinese Herb Dosage

• What is the typical dosage of Da Qing Ye?

  Roughly 9–30 g of the dried leaf in decoction — a wide range, with the upper end reserved for acute, strongly febrile presentations under professional care. The part used is the leaf only; the root of the same plant is a separate herb with its own dose range. Fresh leaf is sometimes used in larger quantity, and the herb is also applied externally as a wash or paste for heat-toxin skin eruptions.

  • Part used — dried leaf (some sources permit fresh leaf, typically at higher weight because of water content).
  • Preparation — standard water decoction; also used topically.
  • Course — traditionally short, because of its very cold nature.

  Source: Sacred Lotus sources & references; cross-referenced against multiple online sources and standard materia medica ranges. Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions for Da Qing Ye?

  Da Qing Ye is very cold, so it is traditionally contraindicated where there is cold from Spleen and Stomach deficiency, and it is not appropriate in the absence of a genuine heat pattern. Using an extremely cold, toxin-draining herb in someone who is already cold or digestively weak is expected to worsen the picture — loose stools, poor appetite, abdominal cold and fullness.

  • Spleen/Stomach cold or deficiency — the primary classical caution.
  • No heat present — not suitable for chronic, deficient, or cold presentations; its use is pattern-driven.
  • Prolonged use — discouraged for the same reason; traditional use is short and acute.
  • Pregnancy and children — best used only under a qualified practitioner, given the strength of the cold.

  Source: Sacred Lotus sources & references; cross-referenced against multiple online sources and materia medica consensus. Traditional-use framing; not medical advice.

Herb-Drug Interactions

• No well-established clinical herb–drug interactions are documented for Da Qing Ye. The leaf shares its major indole-type constituents (indican, isatin, indirubin, indigotin) with the other woad-derived medicinals, and indirubin in particular has been studied pharmacologically, but we could not verify any clinically demonstrated interaction with a conventional medication for the leaf drug specifically. Practitioner awareness is reasonable rather than evidence-based here. (Flagged for practitioner confirmation.)

  Source: constituent profile from PMID 17330218; interaction status reflects the absence of verifiable clinical reports rather than a demonstrated safety finding.

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

Provided as research context — a summary of published biomedical study, not a therapeutic or medical claim.

• Is there modern research on Da Qing Ye (Isatidis Folium)?

  Yes — the woad leaf has a substantial laboratory literature, concentrated on antiviral and anti-inflammatory activity, but the strong human clinical trial evidence that would be needed to support a medical claim has not been established. A 2022 systematic review of the root and leaf drugs catalogued 142 compounds in the leaf (against 304 in the root) and reported antiviral activity in laboratory models against influenza virus, respiratory syncytial virus, and herpes simplex virus.

  • Chemistry — the characteristic constituents are indole alkaloids and their precursors: indican, isatin, indirubin, and indigotin. An LC–MS/MS method has been published for quantifying all four in the roots and leaves of Isatis indigotica, which is how modern quality control distinguishes and standardises these materials.
  • Antiviral (laboratory) — a fractionation study of Folium Isatidis reported that one chemical fraction showed marked activity against herpes simplex virus type 1 in cell culture and in an animal model, with evidence of both direct viral inactivation and inhibition of viral replication. Preclinical work, not a clinical trial.
  • Broad pharmacology reviews — reviews of Isatis indigotica summarise antiviral, antibacterial, anti-inflammatory, and immunoregulatory activity across the leaf and root, alongside traditional clinical use for influenza-like illness, mumps, and hepatitis, while noting that most supporting data remain preclinical.
  • Botanical identity — DNA-barcoding analysis (ITS2 and matK) of 22 samples concluded that the botanical origin of both Isatidis Radix and Isatidis Folium is Isatis indigotica, and supported treating it as distinct from the European dyer’s woad, Isatis tinctoria.
  • Other directions — an Isatis indigotica leaf extract has been assessed for antioxidant and anti-inflammatory activity in a topical cosmetic context. Interesting as a signal of the leaf’s anti-inflammatory chemistry; unrelated to its traditional internal indications.

  Read together, the research supports the plausibility of the traditional heat-toxin indications without confirming clinical efficacy. Treat the traditional pattern-based use as the basis for use, and the research as context.

  Sources: PMID 34543684 (Journal of Ethnopharmacology, 2022 — systematic review of Isatidis Radix and Isatidis Folium); PMID 33779758 (Journal of Pharmacy and Pharmacology, 2021 — Isatis indigotica review); PMID 16323544 (2005 — Folium Isatidis against herpes simplex virus type 1, preclinical); PMID 17330218 (Rapid Communications in Mass Spectrometry, 2007 — indican, isatin, indirubin, indigotin quantification); PMID 24689245 (2013 — DNA-barcoding botanical origin); PMID 33496123 (2020 — textual research on the medicinal blue herbs); PMID 34572971 (Antioxidants, 2021 — leaf extract antioxidant/anti-inflammatory evaluation). Research context, not a therapeutic claim.

Chinese Herb Notes

• What is the difference between Da Qing Ye, Ban Lan Gen, and Qing Dai?

  They are three different medicinals taken from the same plant family: Da Qing Ye is the leaf, Ban Lan Gen is the root, and Qing Dai is the dried indigo pigment processed out of the leaves. This is one of the most common points of confusion in the whole materia medica, partly because all three are translated into English with the words “woad,” “Isatis,” or “indigo.” DNA-barcoding work confirms that the botanical origin of both the root and the leaf drugs is Isatis indigotica.

  How the family sorts out:

  • Da Qing Ye — the leaf (Folium Isatidis / Folium Daqingye). Bitter, very cold; Heart, Lung, Stomach. Strongest of the three for cooling the blood and reducing macules, and favoured for high fever with blood-level heat.
  • Ban Lan Gen — the root (Radix Isatidis). Bitter, cold; Heart, Lung, Stomach. Emphasis on resolving toxin and benefiting the throat. This is the one sold worldwide as a household granule for sore throat and cold-and-flu season, which is why it is far better known to the public than the leaf.
  • Qing Dai — the processed indigo powder (Indigo Naturalis). Salty, cold; Liver, Lung, Stomach. It is not a raw plant part at all but a pigment precipitated from the fermented leaves. Its distinctive emphases are clearing Liver heat to settle convulsions and topical use; internal doses are small because it is a poorly soluble powder.

  Practical rule for readers: before comparing any dose, action, or research finding across sources, first check whether the source means the leaf, the root, or the indigo powder. A modern systematic review of the root and leaf drugs concluded that their differences in traditional use, chemistry, and pharmacology are substantial enough to justify listing them as two separate medicinals rather than one.

  Naming note: Our record gives the pharmaceutical Latin as Folium Daqingye rather than Folium Isatidis. Both appear in the literature, and the difference is meaningful rather than an error: historically the market name “da qing ye” covered leaves from several different indigo-yielding plants (including Baphicacanthus/Strobilanthes cusia and Polygonum tinctorium) before Isatis indigotica became the dominant official source, and textual research traces exactly that shift across the dynasties. The identity field is left unchanged; readers should be aware that older or regional sources under this name may refer to a different botanical species.

  Source: Sacred Lotus sources & references; cross-referenced against multiple online sources and materia medica consensus; botanical-origin and historical-naming points from PMID 24689245 (DNA barcoding of Isatidis Radix and Isatidis Folium) and PMID 33496123 (textual research on the medicinal “blue” herbs); separate-listing conclusion from PMID 34543684.