In 1920 Aleister Crowley founded the Abbey of Thelema in Cefalu, Sicily. Here he undertook the Mysteries of Filth, magical explorations of the limits of human experience through the ritual use of sadomasochism and coprophagia. This paper will explore these experiments, drawing insight from theorists Mary Douglas and Georges Bataille. It will explore Crowley’s use of sadomasochistic practices throughout his magical work, and the implications this has for understanding the concept of the magical relationship. It will consider the young children present at the Abbey, and argue that they acted as a catalyst, confronting Crowley with the artificiality of taboo-constructs, particularly those of disgust. It will explore the sickness which ravaged the Abbey's inhabitants, considering the way the dysentery-afflicted Leah Hirsig represented to Crowley the epitome of Babalon, and the implications this has for understanding the interplay between sickness, filth and the divine across Crowley's corpus.