Catherine Evelyn Smith (April 25, 1947 – August 16, 2020), also known as Silverbag, was a Canadian backup singer, groupie, drug dealer, and legal secretary. Smith served 15 months in the California Institution for Women for injecting actor John Belushi with a fatal dose of heroin and cocaine in 1982.

Smith had been paid for a front-page headline story in the Hollywood tabloid the National Enquirer, where she stated she was the person who injected Belushi with a fatal drug overdose. Smith co-wrote the book Chasing the Dragon (1984) which told her life story; its title alludes to Smith's heroin addiction. Smith appeared prominently in the Bob Woodward book Wired: The Short Life and Fast Times of John Belushi (1984) and was played by Patti D'Arbanville in the 1989 film adaptation.