OBJECTIVES: The objective of this study is to determine the factors that influence satisfaction with non-sedating antihistamines (NSA) among people who suffer from allergies/hay fever. METHODS: An online survey was conducted in September, 2000 on respondents who had been told by a health care professional that they suffer from allergies/hay fever and were recently (within 12 months) prescribed one of three NSAs to relieve their symptoms. Thesample was weighted to ensure the generalizability of the results. Satisfaction was measured according to the medication’s ability to relieve side effects and control symptoms from allergies/hay fever. A total of 4,081 respondents were included in the analysis. RESULTS: (1) The mean satisfaction score for the first time users (defined as never having taken any medication for allergies/hay fever) was higher than those who had used some medication in the past (p<.01) (2) Of the respondents who had a specific choice of medication in mind, those who received their first choice medication had a higher satisfaction score than those who did not (p<.01). (3) The respondents who discussed their medication jointly with their physician had a higher satisfaction score than those whose doctor chose their medication for them (p<.01). (4) Respondents who were not taking any over-the-counter (OTC) medications reported higher satisfaction scores than those who supplemented their NSA with over-the-counter medications (p<.01). (5) Finally, respondents who had never requested a prescription after seeing an advertisement for any medication had a higher satisfaction score than those who did. (p<.01) CONCLUSIONS: The data provides evidence to suggest that past knowledge or experience with NSAs, patient preference, and patient involvement in the treatment decision making process all play a role in determining satisfaction with NSAs. Furthermore, both over-the-counter medication usage and direct-to-consumer advertising are likely to influence how satisfied people are with their NSA.