Librium (also known as: chlordiazepoxide, xanzolam) is a highly addictive central nervous system depressant that has been prescribed for anxiety treatment and alcohol withdrawal treatment since 1960. It is a driving force in the Netflix miniseries, The Queen's Gambit, as the protagonist, Beth Harmon, struggles with her childhood addiction, where she used Librium to enhance her chess studies.
In the miniseries, it was banned from being prescribed to children in 1958. Before then, Methuen Home had regularly prescribed their residents with Librium under the guise that they would "even [their] disposition".
Throughout the show, Librium is also referred to as vitamins, tranquilizers, and, by Harmon, "the pills".