The sluggish development of European generic drug markets depends heavily on demand side factors, and more specifically, patients' and doctors' loyalty to branded products. Loyalty to originator drugs, to the point where originator prices rise upon generic entry has been described as the 'generics paradox'. Originator loyalty can emerge for a plethora of reasons; including costs, perceptions about quality and physician advice. We know very little about the behavioural underpinnings of brand loyalty from the consumer or patient standpoint. This paper attempts to test the extent to which patients are brand loyal by drawing upon Spain's 2002 Health Barometer survey as it includes questions about consumer acceptance of generics in a country with exceptionally low generic uptake and substitution at the time of the study. Our findings suggest that at least 13% of the population would not accept generics as substitutes to the originator. These results confirm evidence of brand loyalty for a minority. Alongside high levels of awareness of generics, we find that low cost-sharing levels explain consumer brand loyalty but their impact on acceptance of generic substitution is very small. Higher cost-sharing and exempting fewer patients from cost-sharing have the potential to encourage generic acceptance.