BackgroundTrends toward legalizing cannabis may increase experimentation with the drug among less experienced users with limited knowledge of possible adverse reactions. This study explores the prevalence, frequency, and levels of distress produced by various acute adverse reactions to cannabis, as well as predictors of these reactions.MethodsThe Adverse Reactions Scale (ARS) was created and administered to a large sample of undergraduate college students (n = 999) who were predominantly white (> 70%), female (> 70%), recreational (> 90%) cannabis users. The ARS was administered in an anonymous online survey measuring demographics, cannabis use patterns, cannabis use motives, personality, and negative affect.ResultsThe most prevalent adverse reactions to cannabis were coughing fits, anxiety, and paranoia, which > 50% of the sample reported experiencing. The most frequently occurring reactions were coughing fits, chest/lung discomfort, and body humming, which occurred on approximately 30–40% of cannabis use sessions. Panic attacks, fainting, and vomiting were rated as the most distressing, with mean ratings falling between “moderately” and “quite” distressing. Multiple regression analyses revealed that lower frequency of cannabis use predicted increased frequency of adverse reactions. Symptoms of cannabis use disorder, conformity motives, and anxiety sensitivity were significant predictors of both the prevalence of, and distress caused by, adverse reactions.ConclusionsRelative to past research, this study provides a more comprehensive account of possible adverse reactions to cannabis, and individual difference variables that predict these reactions. This study has implications for inexperienced cannabis users, as well as medical professionals and budtenders who provide information about cannabis use.