Efficacy and safety of indigo naturalis ointment in Treating Atopic Dermatitis: A randomized clinical trial.
Lin YK, Chang SH, Yang CY, See LC, Lee BH, Shih IH. Efficacy and safety of indigo naturalis ointment in Treating Atopic Dermatitis: A randomized clinical trial. J Ethnopharmacol 2020;250:112477.
Study type: RCT (double-blind, vehicle-controlled; ages 6–65; NCT02669888) · Added to this library August 23, 2026
What the researchers did
Refined indigo naturalis oil (Lindioil) twice daily vs vehicle for 6 weeks in 48 people with atopic dermatitis, including children from age 6.
What they found
Eczema severity (EASI) fell 49.9% on indigo vs 19.6% on vehicle (p=0.024); superior on every secondary endpoint including itch and quality of life; no significant adverse events.
Why it matters
The first randomized trial of a topical Qing Dai preparation in eczema itself — the "clear Heat, cool Blood" ointment beat its own base oil, with pediatric participants included.
Relates to the patterns: Blood Heat · Heat-Toxin
This summary is educational and does not replace care from your child's pediatrician. Evidence tiers matter: a finding in cells or animals is a reason a treatment could work, not proof that it does.
More in Qing Dai Gao
Efficacy and safety of indigo naturalis oil extract (Lindioil ointment) for the treatment of atopic dermatitis: a randomized, crossover, evaluator-blinded, controlled trial.
Yang CY, et al. Efficacy and safety of indigo naturalis oil extract (Lindioil ointment) for the treatment of atopic dermatitis: a randomized, crossover, evaluator-blinded, controlled trial. Front Pharmacol 2025;16:1546589.
Study type: RCT (crossover vs tacrolimus, n=22 adults)
What: Indigo ointment head-to-head against tacrolimus, a standard prescription immunosuppressant cream.
Found: Tacrolimus reduced severity more (−71% vs −41% EASI), but caused local side-effects in 61% of users vs 10% for indigo; indigo also reduced S. aureus colonisation toward healthy-skin levels and shifted the skin microbiome back toward normal.
Why it matters: Honest comparison: the pharmaceutical is stronger, the herb is far gentler — and only the herb showed the antimicrobial, microbiome-restoring action. Different tools for different lesions.
Comparison of indirubin concentrations in indigo naturalis ointment for psoriasis treatment: a randomized, double-blind, dosage-controlled trial.
Lin YK, et al. Comparison of indirubin concentrations in indigo naturalis ointment for psoriasis treatment: a randomized, double-blind, dosage-controlled trial. Br J Dermatol 2018;178(1):124-131.
Study type: RCT (dose-ranging)
What: Four concentrations of indirubin (indigo's key active) in psoriasis, to find the dose-response.
Found: Highest dose: PASI severity down 69%, with 57% of patients reaching PASI75 and 30% PASI90; no severe adverse events over 20 weeks.
Why it matters: A clean dose-response curve is pharmacology's signature that the active is real — indirubin behaves like a drug because it is one.
Clinical assessment of patients with recalcitrant psoriasis in a randomized, observer-blind, vehicle-controlled trial using indigo naturalis.
Lin YK, et al. Clinical assessment of patients with recalcitrant psoriasis in a randomized, observer-blind, vehicle-controlled trial using indigo naturalis. Arch Dermatol 2008;144(11):1457-64.
Study type: RCT (intra-patient, vehicle-controlled, n=42)
What: Crude indigo ointment vs its own base, on matched plaques of the same patients, 12 weeks.
Found: 74% of patients reached clearance or near-clearance on the treated side; severity scores halved relative to control.
Why it matters: Published in the American Medical Association's dermatology journal — the moment topical Qing Dai entered the Western evidence base.
The efficacy and safety of topically applied indigo naturalis ointment in patients with plaque-type psoriasis.
Lin YK, et al. The efficacy and safety of topically applied indigo naturalis ointment in patients with plaque-type psoriasis. Dermatology 2007;214(2):155-61.
Study type: RCT + skin biopsy immunohistochemistry
What: Indigo ointment with before/after biopsies to see what changed in the tissue.
Found: Proliferation marker Ki-67 fell, T-cell infiltration fell, and filaggrin — the skin's key barrier protein — rose in the treated epidermis.
Why it matters: Direct human-tissue evidence that a "Heat-clearing" ointment rebuilds the barrier while calming inflammation — one action, two vocabularies.