The role of disgust in moral psychology has been a matter of much controversy and experimentation over the past 20 or so years. We present here an integrative look at the literature, organized according to the four functions of emotion proposed by integrative functional theory: appraisal, associative, self-regulation, and communicative. Regarding appraisals, we review experimental, personality, and neuroscientific work that has shown differences between elicitors of disgust and anger in moral contexts, with disgust responding more to bodily moral violations such as incest, and anger responding more to sociomoral violations such as theft. We also present new evidence for interpreting the phenomenon of sociomoral disgust as an appraisal of bad character in a person. The associative nature of disgust is shown by evidence for “unreasoning disgust,” in which associations to bodily moral violations are not accompanied by elaborated reasons, and not modified by appraisals such as harm or intent. We also critically examine the literature about the ability of incidental disgust to intensify moral judgments associatively. For disgust's self-regulation function, we consider the possibility that disgust serves as an existential defense, regulating avoidance of thoughts that might threaten our basic self-image as living humans. Finally, we discuss new evidence from our lab that moral disgust serves a communicative function, implying that expressions of disgust serve to signal one's own moral intentions even when a different emotion is felt internally on the basis of appraisal. Within the scope of the literature, there is evidence that all four functions of Giner-Sorolla's (2012) integrative functional theory of emotion may be operating, and that their variety can help explain some of the paradoxes of disgust.