Discourse analysis is an interdisciplinary field of inquiry which has been little employed by public health practitioners. The methodology involves a focus upon the sociocultural and political context in which text and talk occur. Discourse analysis is, above all, concerned with a critical analysis of the use of language and the reproduction of dominant ideologies (belief systems) in discourse (defined here as a group of ideas or patterned way of thinking which can both be identified in textual and verbal communications and located in wider social structures). Discourse analysis adds a linguistic approach to an understanding of the relationship between language and ideology, exploring the way in which theories of reality and relations of power are encoded in such aspects as the syntax, style and rhetorical devices used in texts. This paper argues that discourse analysis is pertinent to the concerns of public health, for it has the potential to lay bare the ideological dimension of such phenomena as lay health beliefs, the doctor-patient relationship, and the dissemination of health information in the entertainment mass media. This dimension is often neglected by public health research. The method of discourse analysis is explained, and examples of its use in the area of public health given.