Dena Dietrich was an American actress.

Dietrich was best known as the face of Mother Nature from a popular, long-running commercial campaign for Chiffon margarine.

Dietrich first spoke what would become a classic commercial catchphrase – "It's not nice to fool Mother Nature!" – in 1971. The commercials had Dietrich dressed in a delicate white gown and a garland of daisies, test-tasting what she thought was her very own natural butter. Informed by a narrator that she was actually eating Chiffon margarine, the character replied with the catchphrase, accompanied by a thunderclap.

Among her TV credits are The Mod Squad, Emergency, Welcome Back Kotter, The Love Boat, thirtysomething, It's Garry Shandling's Show, The Golden Girls, Blossom, NYPD Blue, Murphy Brown, and Mad About You. She also recurred on the soap operas All My Children and Santa Barbara.

Dietrich's film appearances include The Crazy World of Julius Vrooder (with Barbara Hershey), The Wild Party (with Raquel Welch), The North Avenue Irregulars (with Edward Herrmann), Disorganized Crime (with Ed O'Neill and Corbin Bernsen), and Mel Brooks' History of the World: Part I.

Dietrich served as a Screen Actors Guild national board member for nearly a decade.

Dietrich died November 21, 2020, in Los Angeles, California. She was 91.