$OBJECTIVES$: There is sparse evidence regarding the effect of alcohol-advertising exposure on alcohol consumption among heavy drinkers. This study aimed to assess the immediate effects of alcohol-promoting and alcohol-warning video advertising on objective alcohol consumption in heavy-drinking young adults, and to examine underlying processes.

$DESIGN$: Between-participants randomized controlled trial with three conditions.

$METHODS$: Two hundred and four young adults (aged 18-25) who self-reported as heavy drinkers were randomized to view one of three sets of 10 video advertisements that included either (1) alcohol-promoting, (2) alcohol-warning, or (3) non-alcohol advertisements. The primary outcome was the proportion of alcoholic beverages consumed in a sham taste test. Affective responses to advertisements, implicit alcohol approach bias, and alcohol attentional bias were assessed as secondary outcomes and possible mediators. Typical alcohol consumption, Internet use, and television use were measured as covariates.

$RESULTS$: There was no main effect of condition on alcohol consumption. Participants exposed to alcohol-promoting advertisements showed increased positive affect and an increased approach/reduced avoidance bias towards alcohol relative to those exposed to non-alcohol advertisements. There was an indirect effect of exposure to alcohol-warning advertisements on reduced alcohol consumption via negative affect experienced in response to these advertisements.

$CONCLUSIONS$: Restricting alcohol-promoting advertising could remove a potential influence on positive alcohol-related emotions and cognitions among heavy-drinking young adults. Producing alcohol-warning advertising that generates negative emotion may be an effective strategy to reduce alcohol consumption.