Background: This experiment was designed to compare gelatin "shots"-a new procedure for administering alcohol in a laboratory setting-to the alcohol beverage method. We proceeded to test whether the two methods were comparable in terms of alcohol absorption, metabolism, and effects on mood and whether gelatin "shots" were better than the beverage in disguising alcohol in a blind, placebo comparison.
Methods: Healthy volunteers participated in a two-phase trial. In the first phase they completed 2 days of testing during which the effects of alcohol-delivered in beverage (1 day) or gelatin "shots" (alternative day)-on blood and breathalyzer concentrations and mood were assessed. In the second phase participants completed 2 days of testing and were asked to identify if samples contained alcohol or placebo. The presentation of alcohol and placebo and the presentation of beverage or gelatin "shots" were random.
Results: In the first phase there was a significant time-by-condition interaction in the blood alcohol concentration. Two-and-a-half hours after the alcohol was administered, those given gelatin "shots" had slightly lower but statistically significant blood alcohol concentrations. There was a significant time effect for breathalyzer alcohol levels but no condition or condition-by-time interaction. There were no differences between the two methods on any of the subjective mood measures. In the second phase of the study there were differences in the ability to differentiate alcohol from placebo between the two conditions with significantly more participants making errors in the gelatin "shots" than in the beverage condition.
Conclusions: Our findings indicate that gelatin "shots" are an effective method for delivering alcohol to humans in a laboratory setting. This method may be superior to the alcohol beverage mixture in a placebo-controlled design because gelatin "shots" mask the alcohol much better than a beverage and are easier to administer.