Sarsaparilla (Smilax regelii and other closely related species of Smilax) is a vine that bears roots with many useful properties. These vines have long prickly stems and shiny leaves, and numerous reddish-brown roots up to 3 m long. Several species of Smilax are used, but the Jamaican S. regelii (syn. S. officinalis) is the species preferred for commercial use. Sarsaparilla is also grown in Mexico, Central America, and parts of South America. The main uses include the flavouring of beverages, and homeopathic medicine.

Before treatment, the roots are bitter, sticky, and have no smell. Then they are dried and boiled in order to produce the extract. For use in beverages, oil of wintergreen or other flavours may be added in order to mask the natural bitterness of the root. Root beer made from sarsaparilla roots is generally more "birchy" than the more popular, commercial brands.

A popular carbonated sarsaparilla beverage in Queensland, Australia is called Sars. It was named before the health epidemic of the same name, and it was of great entertainment value to visitors to be able to buy a 'Can of SARS'.