"Sweet Leaf" is a song by Black Sabbath from their 1971 album Master of Reality. The song is about recreational cannabis use and its positive effects. The song begins with a tape loop of guitarist Tony Iommi coughing from a joint he was smoking with bandmate Ozzy Osbourne. The song is an early and quintessential example of stoner rock.
The original version of the song has been made available and playable in music video game Guitar Hero 5 on March 29, 2010. A cover of the song is also available for download in the similar Rock Band series.