Chinese Skullcap
LamiaceaeScutellaria baicalensis
Also known as: Huang Qin, Baikal Skullcap, Baical Skullcap
clinical_notes Clinical Summary
Chinese skullcap (Scutellaria baicalensis, Huang Qin) is one of the 50 fundamental herbs of Traditional Chinese Medicine, valued for over 2,000 years to 'clear heat and drain dampness.' Its flavonoids—baicalin, baicalein, and wogonin—exhibit potent anti-inflammatory, antiviral, antimicrobial, and hepatoprotective activity in modern research.
Whole-herb preparations at 3–15 g/day are generally well tolerated, but combination products have been linked to rare hepatotoxicity and the herb has significant interactions with statins, cyclosporine, and potentially warfarin.
Pregnancy Safety
Classical TCM uses Huang Qin in formulas such as Dang Gui San to calm a restless fetus and prevent miscarriage; however, modern human safety data are inadequate. Animal studies showed no fetal malformations at clinical-equivalent doses, but maternal toxicity appeared at 32 g/kg/day. Reserve for TCM practitioner-supervised use.
Lactation Safety
No adequate data on transfer into breast milk or effects on the nursing infant. The bitter-cold nature and documented bioactive flavonoids warrant avoidance unless specifically prescribed.
warning Contraindications
- Concurrent statin therapy (rosuvastatin, simvastatin) (caution)Clinically Proven
- Concurrent cyclosporine (avoid)Theoretical
- History of drug-induced liver injury or active hepatitis (caution)Clinically Proven
- Spleen/Stomach deficiency-cold (TCM) (caution)Theoretical
- Pregnancy (non-classical use) (caution)Theoretical
- Concurrent warfarin or antiplatelet therapy (caution)Theoretical
vital_signs Clinical Profile
Primary Indications
- check_circle Upper respiratory infections
- check_circle Allergic rhinitis
- check_circle Bronchitis
- check_circle Viral infections
- check_circle Hepatitis
- check_circle Inflammatory bowel disease
- check_circle Allergic conditions
- check_circle Dysentery and bacterial diarrhea
- check_circle Damp-heat patterns (TCM)
- check_circle Threatened miscarriage (classical TCM)
- check_circle Tick-borne co-infections (Buhner protocol)
Therapeutic Actions
System Affinities
- check_circle respiratory
- check_circle hepatic
- check_circle cardiovascular
- check_circle gastrointestinal
- check_circle immune
labs Active Constituents
Baicalin
Baicalein
Wogonin
Wogonoside
Oroxylin A
Norwogonin
Scutellarin
β-sitosterol
Rosmarinic acid
Neo-clerodane diterpenoids
history_edu Traditional Use
Traditional Chinese Medicine (TCM)
黄芩 (Huáng Qín)
Nature: cold
- Damp-Heat in the Lungs (yellow phlegm, fever, cough)
- Damp-Heat in the Intestines (dysentery, diarrhea)
- Heat in the Blood causing bleeding (hemoptysis, epistaxis, metrorrhagia)
- Liver-Yang Rising with hypertension
- Restless Fetus (An Tai) with Heat pattern
- Shao Yang syndrome (alternating chills and fever)
First recorded in the Shennong Bencao Jing (ca. 200–250 AD) as a middle-grade herb. Three preparations exist: raw (clears upper-jiao heat), wine-fried (ascends to clear head and Lung heat), and charcoaled (stops bleeding). Incompatibility (Eighteen Antagonisms): avoid with Veratrum (Li Lu).
Traditional Uses Across Healing Systems
While many herbs lack controlled clinical trials, centuries of traditional practice across cultures provide valuable insight into their therapeutic applications.
Clears Heat and Drains Dampness, especially Damp-Heat in the upper and middle Jiao. Used for febrile diseases with cough, yellow sputum, dysentery, jaundice, and to calm restless fetus in Heat patterns.
Li Shizhen famously reported self-treating a severe lung infection with Huang Qin at age 20.
Used in Japanese formulas such as Sho-saiko-to (Minor Bupleurum Decoction) for chronic liver disease and Shao Yang patterns
Kampo Sho-saiko-to historically used for chronic hepatitis B/C but carries pulmonary fibrosis risk when combined with interferon.
Modern Western herbalism uses Chinese skullcap for allergic conditions, asthma, viral infections (including Lyme coinfections per Buhner protocol), and as a component of cancer support formulas
Stephen Buhner's protocols for Bartonella and Mycoplasma prominently feature Chinese skullcap.
spa Parts Used
root
- All primary therapeutic indications
- Decoction (raw root) for heat-clearing
- Wine-processed for upper-jiao heat
Root harvested in spring or autumn of 3–4-year-old plants, scraped of rough bark, and sun-dried. Traditional processing includes slicing while moist, dry-frying with wine (jiu chao), or charring (tan) to modify its properties.
aerial parts
- Less commonly used medicinally
Aerial parts are not the official TCM medicinal part; neo-clerodane diterpenoids in aerial parts may have additional cytotoxic activity.
shield Safety
Contraindications — Evidence Basis
Concurrent statin therapy (rosuvastatin, simvastatin)
Baicalin significantly reduces rosuvastatin plasma levels via OATP1B1 inhibition, potentially reducing lipid-lowering efficacy.
Concurrent cyclosporine
Scutellaria baicalensis decoction significantly decreases cyclosporine bioavailability; avoid in transplant recipients.
History of drug-induced liver injury or active hepatitis
Rare case reports of hepatocellular injury with jaundice onset 1–12 weeks after initiation, often in products combined with black catechu (e.g., Limbrel/Move Free Advanced). Baseline and periodic liver function monitoring recommended. Some evidence (Puri 2019) suggests whole-herb preparations at 1335 mg/day for 444 days did not cause hepatic dysfunction.
Spleen/Stomach deficiency-cold (TCM)
Bitter, cold nature of the herb can worsen patterns of deficiency-cold with loose stools, cold extremities, and poor digestion.
Pregnancy (non-classical use)
Classically used in formulas to 'calm the fetus' (An Tai) for threatened miscarriage; however modern safety data are limited. Mouse organogenesis studies showed maternal toxicity at 32 g/kg/day. Use only under qualified TCM practitioner supervision.
Concurrent warfarin or antiplatelet therapy
Baicalin exhibits antithrombotic activity in vitro with theoretical additive bleeding risk.
Monitoring Parameters
Monitor during use, especially with prolonged or high-dose therapy.
Liver enzymes (ALT, AST, ALP, bilirubin)
Baseline, at 4–6 weeks, then every 3 months during extended useRare but documented cases of drug-induced liver injury, particularly with combination products; whole-herb monotherapy studies show no hepatotoxicity but vigilance is recommended
flagThreshold: ALT or AST >3x ULN or new-onset jaundice: discontinue immediately and refer to hepatology
INR (if on warfarin)
Weekly for first month, then monthlyTheoretical antiplatelet/antithrombotic activity of baicalin may potentiate warfarin
flagThreshold: INR outside therapeutic range: adjust warfarin or discontinue Huang Qin
Statin plasma levels or LDL-C response (if on rosuvastatin/simvastatin)
Lipid panel at 6–8 weeks after initiationBaicalin reduces rosuvastatin AUC via OATP1B1 inhibition
flagThreshold: Unexpected rise in LDL-C: consider herb-drug interaction
Toxicity
Therapeutic oral dose of dried root: 3–15 g/day. No well-defined human toxic dose; rodent LD50 for baicalin >2 g/kg.
Reported: elevated aminotransferases, cholestasis, jaundice, rare pulmonary infiltrates. Acute thrombocytopenic purpura has been reported.
Immediate discontinuation; supportive care; serial LFTs; consult hepatology if elevated ALT/AST >3x ULN or bilirubin elevation. Hepatic injury typically resolves within weeks of discontinuation.
Adverse Effects
CYP Metabolism
Wogonin inhibits CYP1A2 and CYP2C19 in vitro. Baicalin inhibits OATP1B1 (affecting statin uptake) and SLC transporters. Multiple flavonoids can modulate CYP3A4. Clinically significant reduction of cyclosporine and rosuvastatin AUC documented. Use caution with narrow-therapeutic-index drugs.
swap_horiz Interactions
Rosuvastatin
Class: HMG-CoA reductase inhibitor (statin)
Baicalin, a major flavonoid glucuronide in Scutellaria baicalensis, decreases rosuvastatin plasma AUC by 42-47% in OATP1B1*1b/*1b subjects and 21-24% in OATP1B1*1b/*15 carriers through OATP1B1-mediated hepatic uptake induction (14-day 150 mg/d baicalin dosing). This reduces systemic rosuvastatin exposure and potentially LDL-lowering efficacy.
If Chinese skullcap cannot be avoided, monitor LDL-C response at 6-8 weeks; a larger-than-expected LDL reduction is unlikely. Consider switching to a statin less dependent on OATP1B1 (e.g., fluvastatin) or increasing the rosuvastatin dose with lipid monitoring.
Cyclosporine
Class: Calcineurin inhibitor (immunosuppressant)
Multiple-dose baicalin induces intestinal P-glycoprotein, decreasing oral bioavailability of cyclosporine. Additionally, wogonin inhibits CYP1A2 and CYP2C19 and baicalein modulates CYP3A4, making exposure unpredictable. Transplant recipients risk subtherapeutic cyclosporine levels and graft rejection.
Avoid Scutellaria baicalensis in organ transplant recipients or other patients on cyclosporine. If inadvertent exposure occurs, measure cyclosporine trough levels within 3-5 days and monitor for signs of rejection; dose adjustment is often needed.
Theophylline
Class: Methylxanthine bronchodilator
Theophylline is principally metabolized by CYP1A2. Wogonin and baicalein from Scutellaria baicalensis inhibit CYP1A2 in vitro and in vivo, potentially increasing theophylline plasma concentrations and the risk of tachyarrhythmias, tremor, and seizures.
Monitor theophylline serum levels (therapeutic 10-20 mcg/mL) within 1 week of initiating Chinese skullcap. Watch for CNS overstimulation, GI upset, or tachycardia; reduce theophylline dose if levels rise.
Warfarin
Class: Anticoagulant (vitamin K antagonist)
Scutellaria baicalensis flavonoids can inhibit CYP2C9 in vitro (the primary enzyme metabolizing S-warfarin) and display mild antiplatelet activity. Both pharmacokinetic (potential INR elevation) and pharmacodynamic (bleeding) interactions are plausible.
Avoid the combination if possible. If co-administered, check INR weekly for 2-4 weeks after starting or stopping skullcap, and educate patients on bleeding signs.
Clopidogrel
Class: Antiplatelet (P2Y12 inhibitor)
Clopidogrel is a prodrug activated primarily by CYP2C19 (and secondarily CYP3A4). Wogonin inhibits CYP2C19 in vitro, which could impair conversion of clopidogrel to its active thiol metabolite and reduce antiplatelet efficacy — a risk analogous to omeprazole-clopidogrel interactions.
Avoid Chinese skullcap during dual antiplatelet therapy after stent placement or acute coronary syndrome. If alternative is needed, consider ticagrelor or prasugrel (which are less dependent on CYP2C19 activation).
Lithium
Class: Mood stabilizer
Chinese skullcap has documented mild diuretic activity. Lithium renal excretion is highly dependent on sodium and fluid balance; any natriuresis or dehydration can raise lithium levels into the toxic range.
Check lithium serum levels 3-5 days after initiating Chinese skullcap and weekly until stable. Counsel patients on signs of lithium toxicity (tremor, ataxia, GI upset, confusion).
hub Combinations
Synergistic pairings can enhance therapeutic outcomes, while knowing suitable substitutes helps when specific herbs are unavailable or contraindicated.
Classical Formulas
4Goldthread
Traditional UseClassical TCM pairing in Huang Lian Jie Du Tang — both herbs clear heat and dry damp; synergistic broad-spectrum antimicrobial activity against gram-positive and gram-negative bacteria
Foundational formula for heat-toxicity patterns; modern research on Huang Lian Jie Du Tang for sepsis and inflammation
Kudzu
Traditional UseIn Ge Gen Huang Lian Huang Qin Tang (Kudzu, Coptis, and Scutellaria Decoction) — used classically for diarrhea with interior heat; together address muscle-layer heat and damp-heat in the intestines
Classical formula with modern applications for inflammatory bowel conditions and diabetes; paired clinically with metformin in a type 2 diabetes RCT (Shin 2020)
Sweet Wormwood
Traditional UsePaired in Hao Qin Qing Dan Tang — both are bitter and cold, addressing lingering heat in the Shao Yang and gallbladder
Classical formula for post-febrile residual heat with low-grade fever and bitter taste
White Peony
Traditional UseIn Shao Yao Tang (Peony Decoction) — clears damp-heat from the intestines; peony tonifies blood and harmonizes; used for dysentery with blood
Classical Song dynasty formula for damp-heat dysentery
Possible Substitutes
1Andrographis
Moderate EvidenceBoth clear heat and resolve toxicity; Andrographis is acceptable when Chinese skullcap is unavailable or contraindicated
Both have robust evidence for upper respiratory infections
Synergistic Combinations
1Licorice Root
Traditional UseLicorice harmonizes and buffers the cold, bitter nature of Huang Qin, protecting the digestive system; glycyrrhizin provides additional antiviral and anti-inflammatory activity
Common pairing in TCM formulas to mitigate harsh cold herbs
science Studies
Effects of a Scutellaria baicalensis/Crataegus laevigata, magnesium and chromium supplement on stressed individuals: A randomised, double-blind, placebo-controlled, crossover trial
RCTThis double-blind, placebo-controlled crossover RCT enrolled 43 participants (35 analyzed) aged 18-75 who were subjectively stressed but principally healthy, administering a supplement combining Scutellaria baicalensis root and Crataegus laevigata fruit extracts with magnesium and chromium versus placebo for 15 days each. Psychological well-being, sleep quality, and cognitive performance were assessed at days 7 and 15, with and without an observed multitasking stress challenge. Significant time effects were observed in cognitive function assessments and in energy and fatigue reports within the treatment period. Results provide early clinical support for Scutellaria baicalensis-containing combination supplements in the management of subjective stress and related sleep impairments.
Effects of Acacia catechu and Scutellaria baicalensis extract on cognitive function in a healthy adult population: a double-blind, randomized, placebo-controlled trial
RCTThis 4-week double-blind, placebo-controlled RCT (n=85; mean age 43) assessed the cognitive effects of a combined supplement containing 240 mg Scutellaria baicalensis stem extract and 51 mg Acacia catechu heartwood extract (UP326) in healthy adults. Significant time effects were observed across cognitive function assessments (p<0.001) within both groups but without significant differences between supplement and placebo groups. Energy and fatigue reports similarly showed time effects but no between-group differences. Cortisol levels increased significantly over time in both conditions. The results suggest that while cognition improved during the study period, this was not specifically attributable to the Scutellaria baicalensis formulation over placebo in this healthy population.
medication Dosing
decoction
3–15 g dried root
Divided into 2–3 doses daily
Simmer 20–30 minutes. Standard TCM dosing range per Chinese Pharmacopoeia.
capsule
500–1500 mg standardized extract (typically 30–85% baicalin)
2–3 times daily
Up to 1335 mg/day shown safe for hepatic function over 444 days.
tincture
2–5 mL (1:3 in 45% ethanol)
3 times daily
Western herbalist dose range for adult.
powder
1–3 g
2–3 times daily
Can be mixed with warm water or added to formulas.
Disclaimer: This information is largely AI-generated and reviewed by human experts at Evara Health. It is intended for educational and clinical reference purposes only and should not replace professional medical advice.
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