Recent empirical studies have established that disgust plays a role in moral judgment. The normative significance of this discovery remains an object of philosophical contention, however; ‘disgust skeptics’ such as Martha Nussbaum have argued that disgust is a distorting influence on moral judgment and has no legitimate role to play in assessments of moral wrongness. I argue, pace Nussbaum, that disgust’s role in the moral domain parallels its role in the physical domain. Just as physical disgust tracks physical contamination and (...) pollution, so moral disgust tracks social contamination. I begin by examining the arguments for skepticism about disgust and show that these arguments threaten to overgeneralize and lead to a widespread skepticism about the justifiability of our moral judgments. I then look at the positive arguments for according disgust a role in moral judgment, and suggest that disgust tracks invisible social contagions in much the same way as it tracks invisible physical contagions, thereby serving as a defense against the threat of socio-moral contamination. (shrink)