|Previous owners||Procter & Gamble, Prestige Brands International|
Prell is a viscous, pearl green shampoo and conditioner product manufactured by Ultimark Products that according to its maker "...contains a unique 'rinse clean' formula that provides a thick, rich lather for clean, healthy hair."
Prell was introduced by Procter & Gamble in 1947. The original formula was a clear green concentrate packaged in a tube. In 1955 Prell was marketed for women "who want their hair to have that radiantly alive look". A woman held the Prell bottle with her hands on both sides, directly in front of her face. Prell and Head & Shoulders, also made by Procter & Gamble, were the two best-selling shampoos in the United States in June 1977. Procter & Gamble had the highest advertising budget in the shampoo industry. The firm of Wells, Rich, Greene carried out advertising for Prell. Prior to December 1, 1973, Prell billings was coordinated by Benton & Bowles. In advertisements the quasi-liquid Prell would induce a pearl to sink slowly to the bottom of a container. Procter & Gamble sold the brand to Prestige Brands International in November 1999. Prestige then sold Prell, along with its other two shampoo brands, Denorex and Zincon, to Ultimark Products in October 2009 in order to focus more on their two larger segments: over-the-counter healthcare and household cleaning products.
Prell launched an additional version in the late 1990s called Prell Thickening Formula. Instead of being green, this product was colorless and boasted volumizing abilities. It was pulled from the market in 2009, after Prestige Brands sold Prell, along with dandruff shampoo Denorex, to Ultimark. 
In popular culture
Prell's plastic container was used as a selling point in its early years, because it would not break if it fell off a shelf onto the floor. In one of the early 2000 Year Old Man sketches, Carl Reiner asked Mel Brooks what was the greatest invention of all time. Brooks answered, "Liquid Prell" - because an iron lung could fall off a shelf and break, but not Liquid Prell.
In an episode of Drawn Together, Ling-Ling describes his new shampoo (Prell) as his worst lingual enemy; he pronounces it "Plerr", providing another instance of Ling-Ling switching L's and R's. He then asks how "Plerr" can give his hair such shine and body yet "leave his soul with shame and embarrassment".
In the movie The Rock (film) it represented the chemical weapon VX.
In Mad Men Season 6, Episode 11,"Favors," set in 1968, Prell is referenced when the Sally Draper character sniffs a friend's arm, declaring that it smelled like Prell.
In Half Baked Thurgood asks Mary Jane if she uses Prell.
Track two on the album Desert Sessions 5&6, "Letters To Mommy", references Prell: "...Mommy says that daddy's not well/Cause he drinks my liquid Prell..."
During the Comedy Central Roast of Larry the Cable Guy, Nick DiPaolo told Maureen McCormick (one of the roasters) that the phrase "Marcia, Marcia, Marcia!" wasn't Jan but him in the shower at age 12 with a hand full of Prell. (Clearly referring to his crush he had on her as a kid.)
- It's Here-New Extra-Rich Liquid Prell, Mansfield, Ohio News-Journal, February 17, 1955, Page 32.
- All About:Combing the Ailes for a Shampoo, New York Times, June 8, 1977, Page 45.
- P&G Moves Gleem To Burnett, April 14, 1976, Page 50.
- Advertising: VW Strays Return, New York Times, August 29, 1973, Page 55.
- Off The Shelf, New York Times, February 25, 2001, Page CT1.
- Fey, Tina (2011). Bossypants. Little, Brown. p. 56. ISBN 9780316175869.