"Insane in the Brain" is a 1993 single by the American hip hop group Cypress Hill. In addition to hitting number one on the US rap chart, the song also was a mainstream hit, reaching number 19 on the Billboard Hot 100 in 1993. It earned a gold certification from the Recording Industry Association of America and sold 600,000 copies domestically. It was highly successful in other countries. The song was released on the group's Black Sunday album. The popular lyric "Insane in the membrane" is sometimes confused for the title.