Sierra Mist is a multi-lemon-lime flavored caffeine-free soft drink, introduced by PepsiCo in 2000 and rolled out nationally in 2003.
Like many sodas, Sierra Mist contains two ingredients, potassium benzoate and ascorbic acid (vitamin C), which in combination may react to produce benzene. Benzene is a known carcinogen. Sierra Mist has not been shown to contain benzene in levels exceeding the EPA standards for drinking water. 
Complete list of ingredients: carbonated water, high-fructose corn syrup, citric acid, natural flavors, potassium benzoate (preserves freshness), potassium citrate, ascorbic acid and calcium disodium EDTA (protects flavor).
In 2005, a series of improv-based commercials titled "Mist Takes" began airing. It featured Nicole Sullivan, Debra Wilson, Aries Spears, Jim Gaffigan, and Michael Ian Black . In 2006, Kathy Griffin, Tracy Morgan and Guillermo Diaz joined the cast. Also in 2006, a version for Spanish-language channels began airing. The Spanish version stars Diaz and members of the cast of Otro Rollo.
In late 2006 PepsiCo introduced Sierra Mist Cranberry Splash. It was only available during the Winter holiday season. Cranberry Splash returned in the fall of 2007 and 2008 along with a diet version, Sierra Mist Free Cranberry Splash.
In May 2007 Sierra Mist Lemon Squeeze was introduced. This limited edition featured an extra bit of lemon taste and was only available through September 2007.
In December 2007 Pepsi co. trademarked the names Sierra Mist: Undercover Orange and Sierra Mist Free: Undercover Orange. The two sodas launched in the summer of 2008 (with the faces of Steve Carell and Anne Hathaway on their labels) as a marketing tie-in with the release of the Warner Bros new film Get Smart'' on June 20, 2008. Sierra Mist: Undercover Orange and Sierra Mist Free: Undercover Orange are both clear sodas, like regular Sierra Mist and Sierra Mist Free, but have a mandarin orange flavor.
Sierra Mist is an official partner and sponsor of Major League Soccer and two franchises within the league, the New England Revolution and D.C. United.