PROJECT SUMMARY While cigarette smoking has declined over the past two decades, cigar smoking has increased. Cigar smoking is most prevalent among young adults, with cigarillos accounting for the majority of young adult cigar use. About 13% of young adults 18-24 years old currently smoke cigarillos compared to 3.2% of adults > 25 years of age. Cigarillos expose young adults to comparable or higher levels of nicotine and many of the same toxicants and carcinogens as combustible cigarettes, making cigarillo use in young adults a significant public health concern. The rapid growth in available flavors has popularized cigarillo use among young adults. Research suggests that young adults prefer flavored to non-flavored tobacco cigarillos, especially those flavored to taste like fruit or other sweets. However, the factors that underlie such preferences have received little attention. Behavioral theories conceptualize the choice of sweet flavored cigarillos to non-flavored cigarillos as a reflection of greater rewarding and relative reinforcing value. Surprisingly, only two small studies have formally examined the subjective rewarding and reinforcing effects of sweet flavored tobacco, both focused on e-cigarettes. Data on the impact of sweet flavoring on combustible cigarillo use is critical to inform public health and regulatory actions aimed at reducing cigarillo use among young adults. Using validated human laboratory paradigms, the proposed study will be the first to determine if sweet- flavored cigarillos are more rewarding and reinforcing (relative and absolute) than non-flavored cigarillos among young adults. We anticipate that young adults will have a greater hedonic response to sweet flavored versus non-flavored cigarillos (greater subjective rewarding value), increased motivation to consume sweet flavored versus non-flavored cigarillos (greater relative reinforcing value), and greater consumption of sweet flavored versus non-flavored cigarillos (absolute reinforcing value). These three hypotheses will be tested across three separate laboratory visits among 86 young adults (ages 18-24 years old) who are relatively naïve to cigarillos. This is defined as having previously smoked > 3 cigarillos, but not having smoked > 50 cigar products (cigarillos, little cigars, cigars) in their lifetime, and not having consumed > 10 cigar products in the past 30 days. We will examine whether these indices of abuse liability remain significant while controlling for other factors that may underlie the preference for flavoring. This approach will enable us to provide evidence for the impact of sweet flavored cigarillos on subjective, objective, and behavioral outcomes among young adults. Documenting the abuse liability of sweet flavoring in cigarillos will be fundamental to inform evidenced-based public health efforts and support flavor-based regulatory actions. Such actions are necessary to reduce the likelihood that young adults will become persistent cigarillo...