Da Qing Long Tang

Da Qing Long Tang (Major Bluegreen Dragon Decoction), from the Shang Han Lun (Discussion of Cold-Induced Disorders) by Zhang Zhong-Jing.

Actions: Induces diaphoresis and releases the exterior; Clears heat and relieves irritability.

Presentation: Exterior wind-cold syndrome with interior heat: fever and aversion to cold of equal severity, a superficial and tight pulse, body aches, absence of perspiration, irritability, and restlessness.

Cautions:

• Strong diaphoretic that can damage yang qi; contraindicated with spontaneous sweating, aversion to wind, weak pulse or generalized deficiency. Use only as needed, stop when effective, avoid prolonged use or very large doses.
• Profuse sweating may consume yang (weakness, irritability, aversion to cold, insomnia); the source text applies powder to the body to stop sweating (traditionally Long Gu, Mu Li or Nuo Mi powder; baby powder today).

Herb–drug interactions:

• Interferon-induced adverse reactions: in chronic hepatitis C, Da Qing Long Tang (4 pts) or Ma Huang Tang (8 pts) with interferon-beta significantly reduced discomfort, fever, malaise, paresthesia and arthralgia vs interferon alone (16 pts) without reducing antiviral effect

Pharmacological effects reported:

• Temperature regulation: oral dose of 14 mL/kg lowered temperature in febrile rabbits, onset about 90 minutes, mean reduction 0.96 C at 120 minutes
• Antibacterial: inhibitory effects against E. coli and Staphylococcus aureus

Source: Chen JK, Chen TT. Chinese Herbal Formulas and Applications: Pharmacological Effects & Clinical Research. Art of Medicine Press, 2009, p. 45.

Source text: cook Ma Huang first in 9 cups [1,800 mL] water to 7 cups [1,400 mL], skim foam, add the rest and reduce to 3 cups [600 mL]; take 1 cup [200 mL] warm for mild sweating, and stop once sweating occurs. Today use bracketed doses.