In Sweden, male cigarette smoking has declined as snus, a smokeless tobacco product which is low in carcinogenic nitrosamines, has gained popularity among male tobacco users. Epidemiological modelling based on the Swedish experience indicates that there would be major public health gains if a substantial number of current smokers in other countries could also be persuaded to switch to this product. This form of 'tobacco harm reduction' is very controversial in the public health community for many reasons. These include: objections in principle to the use of less harmful but still addictive nicotine products; uncertainties about the long-term effects of these products on health; doubts about the likely interest in and uptake of these products among existing smokers; concerns that increasing the availability of these products will increase the number of new tobacco users and eventually the number of smokers in the population; and anxiety about how the tobacco industry may use these products to undermine current tobacco control policies. This paper concludes with suggestions for a graduated series of policies that may allow exploration of the public health costs and benefits of encouraging smokers to switch to snus.