This article examines current ethics guidelines for recommendations on advocacy as an acceptable activity for epidemiologists. Three sets of guidelines, those produced by the Industrial Epidemiology Forum (IEF), the International Epidemiological Association (IEA), and the Council of International Organizations of Medical Sciences (CIOMS), appear to endorse the role of advocate, although there are differences in their recommendations. The IEF guidelines hint that advocacy is appropriate, the IEA guidelines recommend separating the roles of scientist and advocate, and the CIOMS guidelines recommend advocacy dependent on the quality of epidemiologic research and on causal interpretations of the data. Advocacy in the form of public health recommendations can be justified in terms of the principle of beneficence found in the guidelines, but is a central obligation only if the aims of the profession are enlarged to include not only the study of disease but also a commitment to disease prevention. An important issue in women's health--alcohol and breast cancer--provides an illustrative example.