Tobacco use causes enormous morbidity and mortality because of the high risk of smoking-related diseases and the high prevalence of cigarette smoking. Existing smoking cessation methods only help motivated smokers who are ready to quit, but the vast majority of smokers are pre-contemplators who are neither ready nor willing to attempt to quit. This means that a high proportion of smokers are not adequately served by current strategies for treating tobacco dependence. As cigarettes prematurely kill 50% of long-term users, any additional measure that may reduce death or illness should be given serious consideration. Many addicted smokers are now forced to live and work much of their life in environments in which smoking is prohibited. Most smokers are dependent on nicotine and abstinence from smoking results in tobacco withdrawal and craving, which manifest as clinical symptoms within a few hours of smoking the last cigarette. Craving and withdrawal symptoms can be controlled by supplying nicotine from sources other than cigarettes, such as Nicotine Replacement Therapy (NRT). Clinical studies of short-term abstinence show that all NRT formulations relieve tobacco withdrawal symptoms and craving. Most unaided attempts to decrease health risks by reducing smoking fail because smokers revert to their 'usual' nicotine intake. However, using NRT to reduce smoking allows smokers to reduce their cigarette consumption (and intake of toxic substances in smoke) while maintaining their nicotine dose. Data suggest that smokers who use NRT can significantly reduce the withdrawal symptoms and craving caused by abstaining from cigarettes, and thereby reduce the number of cigarettes/day and maintain these reductions for up to 2 years. The data also indicate that, despite some compensatory smoking behaviour, reduced smoking with NRT results in decreased toxin exposure. In smoking reduction studies, this translated into an improvement in variables that impact on health: cardiovascular risk factors and haemorheology parameters moved towards more healthy (i.e. non-smoker) levels, and pulmonary function improved. The improvements in established cardiovascular risk factors provide objective proof that exposure reduction translates into clinically meaningful health benefits. Furthermore, the known reversibility of many smoking-induced diseases, the mainly linear dose-effect curve and the absence of any indication of threshold effects suggest that additional health benefits may result from smoking reduction. Even more importantly, smoking reduction may move smokers along the behavioural model towards the ultimate goal--stopping smoking. In all three large smoking reduction studies, a number of subjects who were unwilling or unable to stop smoking at baseline were abstinent at 4 months and 1 and 2 years, which clearly supports the concept of smoking reduction as a step towards abstinence. Rather than undermining cessation, smoking reduction appears to increase motivation to quit. The importance of allowing smokers to gradually take control of their smoking was reflected by the increasing point prevalence abstinence rates seen in the long-term studies. When encouraging smoking reduction, it should clearly be emphasised that complete cessation remains the ultimate goal, but smokers in the precontemplation stage need to progress along the behavioural model before becoming receptive to messages about quitting. In conclusion, the evidence presented in this review supports reduced smoking as a legitimate treatment approach that could be pursued by those smokers who are currently unable or unwilling to quit. Sustained smoking reduction can be achieved and maintained with NRT. The corresponding reduction in exposure is associated with tangible health benefits, measured using surrogate markers. Smoking reduction also promotes abstinence in smokers who are unable or unwilling to quit smoking abruptly. NRT is well tolerated for smoking reduction, and nicotine intake does not increase during concomitant use of NRT and smoking.