"So Pure" is a rock song written and produced by Alanis Morissette and Glen Ballard for Morissette's fourth album Supposed Former Infatuation Junkie (1998). While it was released in Japan during the spring of 1999 as the second single, it was released internationally as the album's third single on June 14, 1999 (see 1999 in music), and it is uptempo and reminiscent in sound to the dance pop music Morissette recorded before her third album Jagged Little Pill (1995). One line in the song, "supposed former infatuation junkie", inspired its album's title. The single was released to U.S. radio stations on June 29 and received little play, peaking outside the top twenty on Billboard magazine's Adult Top 40 and Top 40 Mainstream charts. "So Pure" failed to chart on the U.S. Billboard Hot 100 and performed moderately in the United Kingdom, where it reached the top forty. A special 'radio friendly remix' was featured on US promotional singles and was only commercially released on the Australian domestic single.
The single's video, directed by Morissette, featured her and (then boyfriend) actor Dash Mihok as dance partners transitioning through time and style, from ballroom to salsa, swing, tap, contemporary and rave. It was filmed over two days in Toronto. Morissette said of the video, "Over the last year, I'd become enamored with the dancing styles of the '40s in particular, and intrigued by the evolution of dancing throughout the last five decades and the spirit and different kinds of attitudes that fuel them. When it came time to create this video, there was no question that there would be dancing in it and that these different eras needed to be referenced!" The video world-premiered on AOL on June 25 and was the first from a major artist to debut on the internet.