药材 (yào cái) literally means 'medicine materials' — 药 (yào) means 'medicine' or 'drug', and 材 (cái) means 'material' or 'substance'. Together, they refer to natural substances—primarily plant roots, barks, flowers, seeds, fungi, or animal parts—used in traditional Chinese medicine (TCM) for healing, prevention, or regulation of bodily functions. Unlike modern pharmaceuticals, 药材 are typically unprocessed or minimally processed raw ingredients.

These materials are often dried, sliced, or ground before being decocted into herbal teas, made into pills, or used in topical applications. Common examples include ginseng (人参), goji berries (枸杞), and licorice root (甘草). 药材 are sourced from farms, mountains, or wild habitats, and their quality depends heavily on origin, harvest time, and processing method. They form the foundational building blocks of TCM prescriptions, usually combined in formulas tailored to individual conditions.