ABSTRACT: Most previous brief intervention (BI) studies have focused on alcohol or drug use, instead of both substances. Our primary aim was to determine if an alcohol- and drug-use BI reduced alcohol use and increased alcohol treatment services utilization among adult emergency department (ED) patients who drink alcohol and require an intervention for their drug use. Our secondary aims were to assess when the greatest relative reductions in alcohol use occurred, and which patients (stratified by need for an alcohol use intervention) reduced their alcohol use the most. In this secondary analysis, we studied a sub-sample of participants from the Brief Intervention for Drug Misuse in the Emergency Department (BIDMED) randomized, controlled trial of a BI vs. no BI, whose responses to the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) indicated a need for a BI for any drug use, and who also reported alcohol use. Participants were stratified by their ASSIST alcohol subscore: 1) no BI needed, 2) a BI needed, or 3) an intensive intervention needed for alcohol use. Alcohol use and alcohol treatment services utilization were measured every 3 months for 12 months post-enrollment. Of these 833 participants, median age was 29 years-old, 46% were female; 55% were white/non-Hispanic, 27% black/non-Hispanic, and 15% Hispanic. Although any alcohol use, alcohol use frequency, days of alcohol use, typical drinks consumed/day, and most drinks consumed/day decreased in both the BI and no BI arms, there were no differences between study arms. Few patients sought alcohol use treatment services in follow-up, and utilization also did not differ by study arm. Compared to baseline, alcohol use reduced the most during the first 3 months after enrollment, yet reduced little afterward. Participants whose ASSIST alcohol subscores indicated a need for an intensive intervention generally had the greatest relative decreases in alcohol use. These results indicate that the BI was not efficacious in reducing alcohol use among alcohol- and drug-using adult ED patients than the self-assessments alone, but suggest that self-assessments with or without a BI may confer reductions in alcohol use.