In The Matrix, Morpheus offers Neo the red pill to see the truth. The choice appears during a pivotal conversation in which Morpheus explains that the world Neo knows is an artificial reality called the Matrix.
Taking the red pill allows Neo to awaken in the real world, where his body has been kept in a mechanical pod and connected to the Matrix. The blue pill represents returning to his ordinary life and accepting the simulated world without learning what lies behind it. The film uses the two pills as symbols of truth, uncertainty, and the cost of knowledge.
A common mix-up is remembering the red pill as a general symbol of “waking up” while forgetting that the blue pill is the alternative. The 1999 film, written and directed by Lana and Lilly Wachowski, made this red-versus-blue choice one of modern science fiction's most recognizable scenes.