This study will lay the necessary groundwork for future comprehensive research to examine the utility of the neuropeptide oxytocin (OT) as a potential new medication for the treatment of Alcohol use disorder (AUD). OT modulates a number of key systems involved in addiction processes, including dopamine (DA) mesolimbic reward circuitry, and hypothalamic-pituitary-adrenal (HPA) axis and corticotrophin-releasing factor (CRF) stress systems, and has low abuse liability. Our overarching hypothesis is that OT will attenuate several measures thought to drive compulsive alcohol drinking and relapse. Specifically, investigators will examine whether OT decreases acute stress responses, alleviates alcohol withdrawal symptoms, reduces craving and motivation to drink, and decreases alcohol self-administration. Since interactions with alcohol are an important focus of our study, investigators will enroll non-treatment seeking heavy drinkers with AUD in a double blind, placebo controlled inpatient protocol. Subjects will be randomized to receive intranasal OT (40 IU/dose) or placebo 3 times daily. Participants will complete alcohol detoxification; investigators will measure alcohol withdrawal symptoms, craving, and 24-hr urinary free CORT. Participants will then complete 3 laboratory procedures in fixed order. The Trier Social Stress Test (TSST) which includes public speaking and performance of mental arithmetic will be used to examine subjective and physiological stress responses. An alcohol motivated responding (AMR) procedure will be used to examine subjects' responding to earn either drinks or money. A cumulative alcohol-dosing (CAD) procedure will be used to examine physiological and subjective responses across several blood alcohol levels. cortisol (CORT) levels will also be assessed. This study will provide new information on OT efficacy across a range of different measures predictive of alcohol use and misuse, and, if OT shows efficacy, help clarify the mechanism of OT action.