By the Year 2000, deaths related to lung cancer will increase worldwide to 2 million, mainly due to an increase in cigarette smoking by young adults. The control of lung cancer is a multiphased research and application strategy. The identification of cancer risks and causes and the reduction of carcinogen exposure are the first two phases of this strategy. This paper deals with four interventions with a significant potential impact on the consumption of tobacco. (a) A total ban on the sale of tobacco to minors would be one of the most effective measures to reduce the prevalence of smoking among teenagers and would result, in the long run, in a decrease in lung cancer. (b) In developing countries, the production of tobacco is expected to continue to increase until the Year 2000 and to result in a rapid increase in the incidence of lung cancer. (c) The taxation of tobacco is a powerful tool to reduce smoking, especially among teenagers. (d) In order to reduce the incidence of lung cancer, it is crucial that health professionals inform patients about the health consequences of smoking. Cancer chemoprevention, which could reduce the risk of lung cancer among smokers and exsmokers, is an alternative to primary prevention. The very first step in the chemoprevention strategy is to characterize the chemopreventive agents. The investigator can test its inhibitory capacity in vitro or proceed directly to a tumor inhibition study in laboratory animals. Tumor inhibition studies are carried out at the maximum tolerated dose. Compounds which have demonstrated inhibitory activity are then entered in the next phase of the strategy, the study of chemopreventive efficacies. Chemopreventive agents are best classified according to their mechanism in inhibiting the process of carcinogenesis. One of the most promising approaches to cancer chemoprevention is the use of a combination of chemopreventive agents. The National Cancer Institute funded the development of 14 compounds or combinations of compounds as lung cancer chemopreventive agents. Biomarkers of early lesions are generally used to assess the efficacies of the chemopreventive agents in clinical trials. The biomarker should be able to measure the early phase of the carcinogenic process, be relatively inexpensive, and be the least invasive possible. The biomarkers which have been developed for lung cancer are: index of metaplasia of bronchial tissues and exfoliated atypical bronchial cells.(ABSTRACT TRUNCATED AT 400 WORDS)