Caulis Spatholobi — Spatholobus suberectus Dunn (family Fabaceae), the dried vine stem. The common name refers to the red sap that oozes from a cut stem.
Nature and flavour. Bitter and sweet, warm. Liver and Kidney systems.
The one blood mover whose classical reputation includes blood deficiency and not only stasis. The sources describe it as quickening the blood and supplementing the blood at the same time, regulating the menses, freeing the channels and relaxing the sinews, and it is recorded for irregular or scanty menstruation, for amenorrhoea described as blood deficiency with stasis, for a sallow complexion and the vague aching that the texts attribute to blood failing to nourish the sinews, and for numbness, stiff joints and the limb weakness that follows wind-stroke in the traditional account. It is also a common ingredient in contemporary Chinese hospital practice, where it appears in compounds given alongside conventional treatment; that is a clinical decision for the treating team, and the evidence supporting it is limited and is not established.
性味归经。苦、甘，温。归肝、肾经。
活血药中唯一一味古典声誉里带着「血虚」而不只是「瘀」的。古籍既言其活血、又言其补血，兼调经、舒筋活络；记载用于月经不调、经少、血虚夹瘀所致的经闭，面色萎黄与古籍所论血不养筋的酸痛，以及传统所称中风之后的麻木、关节不利与肢体痿弱。它也是当代中医院里的常用药，常出现在与常规治疗并行的复方之中；那是治疗团队决定的事，其支持证据有限，尚未被证实。
性味温和的活血药 —— 正因为温和才常被随手用起来，但它仍然是药。古籍孕期禁用；哺乳期同样慎用，因为这方面的证据根本不存在。月经过多或经期延长者、有出血倾向者、正在服用华法林或其它抗凝药、抗血小板药者，都不该自行加用活血药。真正的风险在名称：不同地域以 Spatholobus、Millettia、Mucuna 等数属的植物作鸡血藤出售，标准品只有密花豆一源；只标中文名的包装不足以作为鉴定依据。注射液是中医院内的剂型，与干藤并非同一物：中药注射剂有其自身的不良反应记录，绝不可出现在医院之外。上述传统用途有文献记载，其现代临床证据有限，尚未被证实。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」。