Using religion to improve health is an age-old practice. However, using religion and enlisting religious authorities in public health campaigns, as exemplified by tobacco control interventions and other activities undertaken by WHO's Eastern Mediterranean Regional Office, is a relatively recent phenomenon. Although all possible opportunities within society should be exploited to control tobacco use and promote health, religion-based interventions should not be exempted from the evidence-based scrutiny to which other interventions are subjected before being adopted. In the absence of data and debate on whether this approach works, how it should be applied, and what the potential downsides and alternatives are, international organizations such as WHO should think carefully about using religion-based public health interventions in their regional programmes.