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泻下攻积力强，清热泻火解毒
泻下力缓，善清上焦血分热毒，活血祛瘀
泻下力减，偏于活血祛瘀，多用于瘀血证
凉血化瘀止血
煎服3–15g；用于泻下通便宜后下(煎5–10分钟)或开水泡服；外用适量。研末吞服每次0.5–2g。
For educational reference only — not medical advice.
大黄含蒽醌类（大黄酸、大黄素、芦荟大黄素）、番泻苷及鞣质，具有泻下、抗菌、抗炎、止血、利胆及一定抗肿瘤作用；泻下作用主要由番泻苷在结肠经细菌代谢释放。
Rhei Radix et Rhizoma contains anthraquinones (rhein, emodin, aloe-emodin), sennosides, and tannins, with stimulant laxative, antimicrobial, anti-inflammatory, hemostatic, choleretic, and some antineoplastic activity; the laxative effect is mediated by colonic bacterial conversion of sennosides to rheinanthrone.
WHO 专论收录大黄作为短期使用的刺激性泻药，并警告不宜长期使用以免电解质紊乱与结肠黑变病。
WHO monographs document Rhubarb as a short-term stimulant laxative and warn against chronic use due to risk of electrolyte disturbance and pseudomelanosis coli.
Brinker 提醒妊娠期、哺乳期及肠梗阻患者禁用大黄，长期使用可致低钾血症和依赖性。
Brinker notes contraindications in pregnancy, lactation, and bowel obstruction; chronic use can cause hypokalemia and laxative dependence.
Bensky 指出大黄后下（约 5–10 分钟）以保留泻下作用，久煎则鞣质成分突出，作用由泻转涩。
Bensky notes that Da Huang should be added late (5–10 min) to preserve its purgative action; prolonged decoction shifts the effect toward astringent due to tannin release.
This section is provided for academic reference only and does not constitute medical advice.
Documented interactions exist with the following Western drug classes. Click to view mechanism, severity, and clinical recommendations.
妇人怀孕、月经期、哺乳期慎用或忌用。脾胃虚寒、血虚气弱及无实热积滞、瘀血者忌服。
苦寒攻下，易伤胃气。脾胃虚寒者不宜。孕妇、月经期、哺乳期妇女忌用或慎用。长期服用可致继发性便秘、结肠黑变病。大剂量可引起腹痛、腹泻、恶心呕吐。
味苦，寒。主下瘀血，血闭寒热，破癥瘕积聚，留饮宿食，荡涤肠胃，推陈致新，通利水谷，调中化食，安和五脏。
下品
@misc{bencaodian-da-huang,
author = {{Bencaodian Editorial}},
title = {Dà Huáng 大黄 (Rhubarb Root and Rhizome) — Rhei Radix et Rhizoma},
year = {2026},
howpublished = {Bencao Dian: A Bilingual Knowledge Graph of Traditional Chinese Medicine},
url = {https://bencaodian.org/en/herbs/da-huang},
urldate = {2026-04-09},
note = {CC BY-SA 4.0}
}