Among the most popular motifs in Francis Bacon’s painting is the gaping mouth. In some works the expression appears to be a scream, while elsewhere the mouth is open, replete with upper and lower teeth, but beyond that it is unclear whether we are seeing a mouth that is screaming or making some other expression. This article conveys the importance of the mouth as a “lever” for prising apart the human. Through the open mouth Bacon exposes the human-animal and reduces the mouth—as an organ of speech, reason and humanity—to its primal and pre-linguistic function. In demonstrating this it will be argued that rather than focusing exclusively on the scream, more attention needs to be paid to the gaping mouth and its significance in Bacon’s œuvre.