Root beer is a sweet North American soft drink traditionally made using the root bark of the sassafras tree Sassafras albidum or the vine of Smilax ornata (known as sarsaparilla; also used to make a soft drink called sarsaparilla) as the primary flavor.

[3] Major root beer producers include PepsiCo, Coca-Cola Company, Dad's, Keurig Dr. Pepper, Sprecher, and A&W.

[11] In 1919, Roy Allen opened his root-beer stand in Lodi, California, which led to the development of A&W Root Beer.

[1] While sassafras is no longer used in commercially produced root beer and is sometimes replaced with artificial flavors, natural extracts with the safrole distilled and removed are available.

Some manufacturers used small amounts of starch (e.g. from cassava) with natural surfactants to reproduce the familiar foaming character of sassafras-based root beer.

[17] Although this beverage's popularity is greatest in North America, some brands are produced in or imported by other countries, including Australia, the United Kingdom, Malaysia, Argentina, Germany, the Philippines, Singapore, Taiwan, South Korea, Indonesia, Sweden, Vietnam,[18] and Thailand.

While no standard recipe exists, the primary ingredients in modern root beer are filtered water, sugar, and safrole-free sassafras extract, which complements other flavors.

Soybean protein or yucca are sometimes used to create a foamy quality, and caramel coloring is used to make the beverage brown.

Alcoholic and non-alcoholic traditional root beers make a thick and foamy head when poured, often enhanced by the addition of yucca extract, soybean protein, or other thickeners.