Laws and treaties compel countries to inform the public about harmful chemicals (constituents) in cigarette smoke. To encourage relevant research by behavioral scientists, we provide a primer on cigarette smoke toxicology and summarize research on how the public thinks about cigarette smoke chemicals. We systematically searched PubMed in July 2016 and reviewed citations from included articles. Four central findings emerged across 46 articles that met inclusion criteria. First, people were familiar with very few chemicals in cigarette smoke. Second, people knew little about cigarette additives, assumed harmful chemicals are added during manufacturing, and perceived cigarettes without additives to be less harmful. Third, people wanted more information about constituents. Finally, well-presented chemical information increased knowledge and awareness and may change behavior. This research area is in urgent need of behavioral science. Future research should investigate whether educating the public about these chemicals increases risk perceptions and quitting.