Formulas Fatal to the Flesh is the fifth studio album by American death metal band Morbid Angel, released on February 24, 1998 by Earache Records. The Satanic-themed lyrics of the band's previous albums had been replaced with lyrics about the Old Ones, which would become the primary source of Morbid Angel's lyrical content from this point on, with some lyrics written in Sumerian. This is the first album to feature singer/bassist Steve Tucker, who replacing David Vincent.
The title refers to the biblical symbol of the Antichrist. The letter "F" is the 6th letter of the alphabet; therefore, it could be read as "6ormulas 6atal to the 6lesh" or 666 for short, the number of the Beast.