Public health communication campaigns have been credited with helping raise awareness of risk from chronic illness and new infectious diseases and with helping promote the adoption of recommended treatment regimens. Yet many aspects of public health communication interventions have escaped the scrutiny of ethical discussions. With the transference of successful commercial marketing communication tactics to the realm of public health, consideration of ethical issues becomes an essential component in the development and application of public health strategies. Ethical issues in public health communication are explored as they relate to eight topics: 'targeting' and 'tailoring' public health messages to particular population segments; obtaining the equivalence of informed consent; the use of persuasive communication tactics; messages on responsibility and culpability; messages that apply to harm reduction; and three types of unintended adverse effects associated with public health communication activities that may label and stigmatise, expand social gaps, and promote health as a value. We suggest that an ethical analysis should be applied to each phase of the public health communication process in order to identify ethical dilemmas that may appear subtle, yet reflect important concerns regarding potential effects of public health communication interventions on individuals and society as a whole.