The nature of disgust as it relates to psychopathology is described. Evaluative conditioning, an important theory for understanding the acquisition and maintenance of disgust reactions, is discussed, and linked with the general theory of disgust by Rozin and Fallon (1987). The empirical literature on the role of disgust in psychopathology, primarily phobias and general problems of fearful avoidance, is covered, as well as cognitive biases and distortions. Finally, a hierarchy of psychopathology influenced by disgust is presented. Keywords: disgust; anxiety; avoidance; conditioning While disgust has been considered to be a basic emotion since the time of Darwin (1872/1965), it has only recently enjoyed increased attention in the empirical literature. A search of the Psychlnfo database yields 770 references for the key word "disgust," which stands in stark contrast to the 26,750 references found for "fear," another basic emotion. A search with the key word "happiness," an understudied basic emotion like disgust, still uncovered 4,108 references. Clearly, there is a dearth of literature examining disgust. However, since the publication of the seminal article by Rozin and Fallen (1987), which proposed a theoretical reconceptualization of disgust, research on disgust has seen a marked increase with approximately three-quarters of the empirical literature having been published since 1987. Despite this marked increase in attention, a myriad of questions concerning disgust remain unanswered. This article aims to briefly explain the fundamental theory of disgust as well as describe the possible role of evaluative conditioning in the acquisition and maintenance of the disgust response. We will also briefly describe the current status of treatment effects on disgust reactions, cognitive processing of disgust information, and accessibility of disgust related cognitions. Finally, we will propose a hierarchy of disorders that are influenced by the presence of disgust. THE EMOTION OF DISGUST: AN OVERVIEW As explained in their reconceptualization of disgust, Rozin and Fallen (1987) define "core disgust" as a food-related emotion of oral revulsion. This is consistent with the limited literature that existed prior to this publication that viewed disgust as an evolutionarily adaptive response to noxious oral stimuli (Angyal, 1941; Darwin, 1965/1875). However, Rozin and Fallon (1987) further proposed that disgust has contaminating properties that were governed by the laws of sympathetic magic. These laws are comprised of the law of contagion and the law of similarity. The law of contagion is well summarized in the pithy phrase "Once in contact, always in contact." According to this law, disgusting objects transfer their disgusting properties to nondisgusting objects through contact. These disgusting properties remain even after physical contact has ceased and are dose-insensitive (i.e., even brief contact is sufficient to transfer the full compliment of disgusting properties). second, the law of similarity states that objects that are physically similar to disgusting objects are deemed to be more disgusting. For example, Rozin, Millman, and Nemeroff (1986) noted that fudge would be more acceptable food if shaped like a muffin than if it were shaped like feces. Later work began to uncover other domains that are unrelated to concerns regarding oral incorporation, yet were characteristic of core disgust. Animal-nature disgust refers to any aspect of life that reminds humans of their animal nature. Such disgust elicitors are typically either hidden (i.e., defecation) or humanized (i.e., funerals) (Rozin, Haidt, & McCauley, 1999). The domain of interpersonal disgust is stimulated by contact with aspects of undesirable people. For example, Rozin, Haidt, McCauley, Dunlop, and Ashmore (1999) found that less than half of their sample of undergraduate students was willing to put the hat of a Nazi officer on their head. …