What is Long Dan Cao? Are Long Dan, Jian Long Dan and Huang Lian the same?
Prescriptions often write Long Dan Cao (龙胆草); the pharmacopoeial name is Long Dan, the dried root and rhizome of Gentiana manshurica, G. scabra, G. triflora or G. rigescens. The official name is Gentianae Radix et Rhizoma. The first three are called Long Dan; the last is Jian Long Dan—one monograph. Huang Lian is Coptis rhizome: bitter-cold, clears heat, dries damp and resolves toxin, entering Heart, Spleen, Stomach and Large Intestine—not dedicated to draining Liver-Gallbladder. Do not swap in ornamental gentian flowers or anonymous “grass gentian.”
What are the TCM properties and traditional uses of Long Dan Cao?
According to the Chinese Pharmacopoeia, Long Dan is bitter and cold, enters the Liver and Gallbladder channels, and acts to clear heat and dry damp, and drain Liver-Gallbladder fire. It is used for damp-heat jaundice, swelling and itch of the genitals, vaginal discharge, eczema and itch, Liver-fire red eyes, tinnitus and deafness, rib-side pain and bitter taste, persistent erection, and fright-wind convulsions. Bitter-cold and descending—suited to Liver-Gallbladder damp-heat and excess fire, not to Spleen-Stomach deficient cold, patterns without damp-heat excess fire, or Yin deficiency with fluid damage.
How do you choose Long Dan versus Jian Long Dan? Is a special decoction needed?
The pharmacopoeia lists one set of actions; gentiopicroside limits are higher for Long Dan than for Jian Long Dan. Wash, moisten through and cut segments; it goes in the pot with the rest. The taste is extremely bitter, so the dose stays small. Taken on an empty stomach it more injures the Stomach—prefer after meals. External decoction may wash genital eczema; keep it out of the mouth and eyes.
What is the usual dosage? Can it be steeped daily to clear Liver fire?
The pharmacopoeial decoction dose is 3–6 g. It is not a daily “Liver-clearing tea.” Bitter-cold most injures the Spleen and Stomach; without excess fire and damp-heat, clearing only ruins. Liver-fire red eyes and lower-jiao damp-heat may enter Long Dan Xie Gan Tang for a short course, prescribed—not a self-made long drink.
What are the contraindications? Can it be used in pregnancy?
Avoid in Spleen-Stomach deficient cold and when there is no damp-heat excess fire; use caution in Yin deficiency with fluid damage. Bitter-cold injures the Stomach and damages fluid. Pregnancy and lactation need a practitioner—not a daily fire-clearing tea. Stop at once if epigastric pain, vomiting, loose stool or poor appetite appears. Patent Long Dan Xie Gan Wan must use a safe Mutong species; do not use old formulas containing Guan Mutong (Aristolochia).
Can Long Dan Cao drain Liver fire, abate jaundice, stop itch and brighten the eyes?
It can help Liver-Gallbladder damp-heat and excess fire. Red eyes, bitter taste, genital itch and discharge, eczema, deafness and rib-side pain often join Scutellaria, gardenia, Bupleurum, plantago seed, angelica and raw rehmannia in Long Dan Xie Gan Tang. Jaundice joins virgate wormwood and gardenia. Fright-wind needs extinguishing-wind herbs and emergency care. It drains excess fire and damp-heat—not a specific for every red eye, every hepatitis or every itch. High fever with convulsions and acute jaundice need a physician.
Can Long Dan Cao be drunk daily as a Liver-clearing, blood-pressure or detox tea?
No. It is among the bitterest, coldest roots in the pharmacopoeia and is only for short courses of excess fire and damp-heat. “Gentian clears the Liver, lowers pressure and detoxes” does not replace hepatology, hypertension and dermatology. Patent pills should not be taken long without a pattern. Draining Liver-Gallbladder fire should be a 3–6 g short formula that also protects Stomach Qi.
How do you choose among Long Dan Cao, Huang Qin, Huang Lian, Xia Ku Cao and Yin Chen?
Gentian is bitter-cold: dedicated to draining Liver-Gallbladder excess fire and clearing lower-jiao damp-heat. Scutellaria is bitter-cold: clears heat, dries damp, resolves toxin, stops bleeding and calms the fetus, entering Lung, Gallbladder and Large Intestine. Coptis is bitter-cold: clears heat, dries damp and resolves toxin, entering Heart, Spleen and Stomach—stronger for middle-jiao damp-heat. Prunella is acrid-bitter-cold: clears Liver fire and dissipates binds, leaning to scrofula and night eye pain. Virgate wormwood is bitter-acrid and slightly cold: dedicated to clearing and disinhibiting damp-heat and disinhibiting the gallbladder to abate jaundice. Liver-Gallbladder damp-heat with red eyes and genital itch favors Long Dan; jaundice favors Yin Chen; middle-jiao damp-heat favors Huang Lian. They may be paired; all are forbidden when there is deficient cold and no fire.
Which herbs is Long Dan Cao combined with? What are the representative formulas?
Liver-Gallbladder excess fire and damp-heat join Scutellaria, gardenia, Bupleurum, Alisma, plantago seed, angelica, raw rehmannia and licorice in Long Dan Xie Gan Tang. Modern practice must use Chuan Mutong or Tetrapanax, never Guan Mutong. Liver fire with constipation may join rhubarb and aloe in Dang Gui Long Hui Wan-type formulas. Write Long Dan or Long Dan Cao, keep the dose small, and pair licorice and angelica to protect the Stomach.
How do you choose and store Long Dan Cao?
Choose slender roots, pale yellow to yellow-brown, a yellowish-white cortex on section and an intensely bitter taste. Long Dan often shows upper transverse wrinkles; Jian Long Dan sheds a membranous bark and lacks those wrinkles. Mold, damp, a bland taste and excess debris are inferior. Store dry. Buy pharmacopoeial Long Dan slices; do not replace them with the whole herb, the inflorescence or anonymous bitter weeds.
