"Sweet Leaf" is a song by Black Sabbath from their third studio album Master of Reality, released in 1971. It is considered as one of the band's signature songs. It was included on their initial greatest hits compilation We Sold Our Soul for Rock 'n' Roll (1976).
The song begins with a tape loop of guitarist Tony Iommi coughing from a joint he was smoking with bandmate Ozzy Osbourne. The song refers to marijuana, which the band was using frequently. The title of the song was taken from a packet of Irish cigarettes which said "It's the sweet leaf".