Hypochondriasis (HC) involves preoccupation with fears of having a serious medical illness based on the misinterpretation of benign bodily perturbations. Individuals with HC also perform behaviors such as checking and reassurance-seeking presumably to reduce health-related fears. Experimental behavioral analyses of HC symptoms, however, are lacking. In the present study, 27 patients with HC were exposed to personally relevant health-related stimuli under one of two conditions: (a) subsequently performing safety-seeking behaviors (e.g., checking) (n=14) or (b) subsequently being instructed not to perform such behaviors (n=13). In both groups, subjective anxiety and urges to perform safety behaviors were monitored for 1h. Results indicated that exposure to the personally relevant health trigger provoked anxiety and urges to perform safety behaviors. For patients who performed such behaviors, these feelings were reduced. For patients who did not, a more gradual reduction of anxiety and urges was observed. Findings are discussed in terms of the conceptualization and treatment of HC behavior, and are relevant to HC's possible relationship to panic and obsessive-compulsive disorder.