Dioscorea bulbifera L. (Dioscoreae Bulbiferae Rhizoma)
Nature and flavour. Bitter and cold; Lung and Liver systems.
Traditionally classed as transforming phlegm, dissipating masses and reducing goitre, as clearing heat and cooling the blood, and as checking bleeding. Recorded for goitre and thyroid enlargement, for scrofula and other phlegm masses, for cough with blood, and for bleeding attributed to heat in the blood. It belongs to the same pre-modern observation about neck swellings that produced the kelp and sargassum pair, and like them it was used long before the physiology of the thyroid was understood. It is also a yam, and several Dioscorea species are eaten as food — 黄药子 is not among the ones generally treated as food.
性味归经。苦，寒；归肺、肝经。
传统归类为化痰散结消瘿、清热凉血、止血。古籍用于瘿瘤（甲状腺肿大）、瘰疬等痰结肿块、咳血，以及血热所致出血。它属于前现代关于颈部肿大的观察所催生的药物之一，与昆布、海藻同源，同样在甲状腺生理被认识之前即已入药。本品亦属薯蓣属，该属若干种作食物食用，但黄药子不在通常被视为食物的品种之列。
本页诸药中，此味的脏器损伤记录最为明确。已发表的病例报告与系列病例记载了黄药子所致肝损伤 —— 转氨酶升高、黄疸，部分报告为重症甚至致死性肝炎，可见于常规药用剂量，有的在连续用药数周后累积出现，有的一个疗程后即发生，再次服用可复发。已有肝病、肝功能异常或经常饮酒者不应服用；服用期间若出现恶心、食欲减退、尿色加深或皮肤眼白发黄，应立即停用并就医评估。甲状腺肿大须先明确诊断并做甲状腺功能检查，不应自行选药。古籍记载其可致胃肠不适。孕期与哺乳期安全性未确立。