Tobacco use is one of the greatest public health threats and largest contributors to the global burden of preventable death and disease, resulting in over 8 million global tobacco-related deaths annually. Nicotine is the primary addictive constituent of tobacco. Research demonstrates that nicotine produces reinforcer value-enhancing effects which may contribute to tobacco use above and beyond the primary reinforcing effects of nicotine. Although smoking rates have generally decreased over the past few decades, smoking rates among persons with alcohol use disorder (AUD) remain as high as 50 to 80%. Persons with AUD who smoke also exhibit greater alcohol consumption than nonsmoking persons with AUD. Alcohol is commonly consumed in mixed solution with other appetitive reinforcers— frequently sugar carbohydrates or noncaloric sweeteners that increase the palatability of alcohol. Sweetening alcohol leads to higher rates of alcohol consumption and intoxication and a growing body of research indicates the consuming alcohol mixed with noncaloric sweeteners results in even greater intoxication due to faster gastric emptying. For all these reasons, a comprehensive understanding of tobacco use, heavy alcohol use, and the comorbidity between nicotine and alcohol dependence must consider the value-enhancing effects of nicotine in conjunction with the various nonalcoholic sensory and appetitive reinforcers that commonly accompany alcohol consumption. Our long-term objective is to elucidate how the value-enhancing effects of nicotine may contribute to increased alcohol consumption and heightened risk of AUD in tobacco users, and thereby inform treatment strategies aimed at smoking cessation and curtailing problematic drinking. To that end, the proposed research will employ a behavioral economic demand methodology to characterize and compare the value-enhancing effects of nicotine on a range of caloric and noncaloric appetitive reinforcers, with or without alcohol,