Rhizoma Corydalis Decumbentis — Corydalis decumbens (Thunb.) Pers. (family Papaveraceae), the dried tuber
Nature and flavour. Bitter and slightly acrid, warm. Liver system.
An early-spring plant with a name that describes its harvest window: 夏天无 means nothing by summer, because the aerial parts die back early and the tuber has to be lifted in spring. It quickens the blood, relieves pain, dispels wind and damp, and is recorded for headache, for the aching and numbness of wind-damp obstruction, for pain and swelling after knocks and falls, and in the modern Chinese literature for the limb pain and impaired movement that follow wind-stroke. Its best-studied constituent is not the whole herb but one molecule: the tuber yields tetrahydropalmatine, an isoquinoline alkaloid that also occurs in the related Corydalis yanhusuo and that has been studied on its own as a sedative and analgesic compound. That research is not evidence for the traditional uses of the tuber — the traditional uses are recorded, and the modern clinical evidence for them is limited and is not established.
性味归经。苦、微辛，温。归肝经。
一味早春植物，名字说的就是采收窗口：夏天无，即入夏则地上部分已无，须在春季采挖块茎。功能活血止痛、祛风除湿；记载用于头痛，风湿痹阻所致的酸痛麻木，跌扑损伤的肿痛，现代中文文献亦载其用于中风之后的肢体疼痛与活动不利。研究得最充分的不是全草，而是一个分子：本品味含延胡索乙素（四氢帕马丁），属异喹啉类生物碱，同亦见于近缘的延胡索，曾作为镇静与镇痛成分被单独研究。那份研究不能作为本品传统用途成立的证据 —— 传统用途有文献记载，其现代临床证据有限，尚未被证实。
这是本批中药理上最需要谨慎的一味。延胡索乙素有镇静作用：嗜睡、头晕、反应变慢均为有记载的效应，驾车、操作机械与饮酒都不该与它同时。已有与含延胡索乙素制品相关的肝损伤报告，故有肝病者、或肝酶升高而从未查明原因者不应服用；服用期间出现黄疸、尿色深或不明原因的乏力，应停用并就诊。孕期与哺乳期禁用；作为活血药，月经过多及合用抗凝、抗血小板药时同样谨慎。紫堇属块茎细小且多采自野生，流通中的掺伪与错标已有记载；没有拉丁名的包装不足以作为鉴定依据。中风后遗症、持续头痛与慢性关节痛，都该先去查明诊断，而不是凭一个名字买味药来吃。任何使用都须在合格执业者监督下进行；本页刻意不回答「该用多少」。