Microbicides are most usually conceptualised within a disease prevention framework and studies usually define acceptability in terms of product characteristics, willingness to use and risk reduction. This starting point has led to assumptions about microbicides which, rather than being challenged by empirical studies, have tended to foreclose the data and subsequent conceptual models. Few studies take an emic ('insider') perspective or attempt to understand how microbicides fit into the broader context of women's and men's everyday lives. As part of the integrated social science component of the MDP301 Phase III microbicide trial, in-depth interviews were conducted with female trial participants in South Africa, Zambia, Tanzania and Uganda. Women's experiences of the gel challenge several assumptions that have commonly been reiterated about microbicides. Our analysis suggests that current definitions and conceptual frameworks do not adequately account for the range of meanings that women attribute to gel. Even within the context of a clinical trial, it is possible to obtain a richer, ethnographic and cross-cultural concept of acceptability based on women's practice and emic interpretations. We now need to move beyond limited notions of acceptability and consider how microbicides fit into a more holistic picture of women's and men's sexuality and sexual health.