About Ban Lan Gen
TCM 'heat-clearing, toxin-resolving' herb traditionally used during respiratory infectious outbreaks; heavily promoted in China during SARS, H1N1, and COVID-19 despite absence of high-quality clinical evidence. Distinct from Isatis Leaf (Da Qing Ye) — different plant part with different chemistry and traditional indications. Contains indirubin, indigo, indigoticone, and epigoitrin. Antiviral and anti-inflammatory activity has been demonstrated in vitro and in animal models, but no high-quality RCTs in Western literature support clinical efficacy in healthy adults. Reports of allergic reactions and rare hematologic side effects exist in the Chinese pharmacovigilance literature.
What Ban Lan Gen supports
- TCM herb traditionally used during seasonal respiratory illness for 'heat-clearing'
How much Ban Lan Gen to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
500–1500
mg
Traditional use only — no clinical efficacy threshold established. TCM decoction equivalent is 9–15 g raw root; even at a 10:1 extract ratio the floor sits at ~900 mg. Sub-500 mg supplement doses are folk-symbolic, not translated decoctions.
Clinical evidence
Limited clinical evidence. No modern RCTs in healthy adults; traditional use only.
Reference