sarsaparilla, common name for various plants belonging to two different classes and also for an extract from their roots, formerly much used in medicine and in beverages. True sarsaparilla is obtained from various tropical American species of the genus Smilax (which also includes the greenbrier) of the family Smilacaceae, sometimes joined in the Liliaceae (lily family). These have thick rootstalks and thin roots several feet long. Other plants used as substitutes for sarsaparilla include the wild sarsaparilla (Aralia nudicaulis, although S. glauca also bears that name) and the American spikenard (A. racemosa), both North American plants of the family Araliaceae (ginseng family). The Liliaceae are classified in the division Magnoliophyta, class Liliopsida, order Liliales. The Araliaceae are in the class Magnoliopsida, order Apiales.

Aromatic flavouring agent originally made from the dried roots of several tropical smilax vines. Native to the southern and western coasts of Mexico to Peru, the plants are large, perennial, climbing or trailing vines with short, thick, underground stems that produce many prickly, angular, aboveground stems supported by tendrils. Once a popular tonic, sarsaparilla now is blended with wintergreen and other flavours and used in root beer and other carbonated beverages, or to flavour and mask the taste of medicines. In North America, the strongly aromatic roots of the wild sarsaparilla (Aralia nudicaulis) and false, or bristly, sarsaparilla (A. hispida), of the ginseng family, are sometimes substituted for true sarsaparilla.

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