Purpose – The purpose of this paper is to examine how health consciousness and nutrition self-efficacy influence attitudes towards and use of nutrition labels, the moderating effect of nutrition knowledge between health consciousness and nutrition label attitude, and the impact of the consumer’s ethical evaluation of a business on nutrition label use. Design/methodology/approach – This study proposes an integrative model that includes health consciousness, nutrition self-efficacy, nutrition knowledge, nutrition label attitude, ethical evaluation, and nutrition label use. Empirical data were collected from a famous website in Taiwan by a non-ordered questionnaire to decrease the priming effect, and 306 valid questionnaires were collected. The collected data were analysed using SPSS and AMOS software. Findings – The results show that both health consciousness and nutrition self-efficacy have direct effects on nutrition label attitude, and this attitude will influence label use. There is a moderating effect of nutrition knowledge, in terms of both subjective and objective nutrition label knowledge, between health consciousness and nutrition label attitude. However, the moderating effect in the low nutrition label knowledge group is slightly greater than in the high nutrition label knowledge group. The consumer’s ethical evaluation of businesses affects nutrition label use. Originality/value – This study is the first to indicate that nutrition label knowledge, both subjective and objective, will moderate the relationship between consumers’ health consciousness and their attitude towards nutrition labels. Furthermore, this study affirms the relationship between the consumer’s ethical evaluation of a firm and nutrition label use.