The prospect of a threat to one's health or an opportunity for improved health can spark emotional reactions--the fear of an illness or the hope of a healthier life. People are increasingly turning to the Internet to search for information related to such health issues. However, the dizzying amount of online health information--some of it of dubious quality--makes the task of finding trustworthy and relevant health information difficult. One way to address this dilemma is to utilize technology's ability to provide users with customized content based on their unique desires and preferences. Grounded in the literatures on emotions, health information seeking, and customization, one approach to improving the efficiency and effectiveness of the health information seeking process would be to craft customized search engine results based on the user's situational emotion state. Further customizing of health search results based on dispositional aspects of the user's identity--in addition to the situational emotion--is a conceptually promising approach to improving the health information seeking process. This dissertation examined the relationship between types of emotional experiences and health information seeking as well as the interplay of emotion states and customization in the health information seeking process. The results revealed that discrete emotions have an important impact on multiple steps in the health information seeking process, from search query generation to post-search cognitions, attitudes, and behaviors. Additionally, the results indicate that customizing health-related search results based on situational factors may not be as effective as customizing search results based on dispositional aspects of a user's identity. Theoretical, methodological, and public health implications are discussed and directions for future research in this domain are offered. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]