Physicians may be hesitant to advise their patients to give up cigarette smoking partly because they doubt their own effectiveness. The three studies cited in this paper indicate that physicians can help their patients quit smoking if they briefly explain the benefits of quitting and provide concrete advice on how to go about it. This advice is effective primarily with light smokers. If smokers require medical care at least as frequently as nonsmokers and if physicians advise them (during routine care) to quit smoking, some 38 of the 54 million smokers could be reached in a single year. Further research is needed in areas such as physician motivation and the provision of information on smoking.