WHY IT MATTERS: Patients who use cannabis and alcohol together, or who are considering cannabis as a tool to reduce drinking, should know that the evidence for this substitution effect is preliminary and does not yet support cannabis as a clinically validated alcohol reduction strategy. CLINICAL OVERVIEW: The relationship between cannabis and alcohol use is a genuinely complex area of pharmacology, with some research suggesting that certain THC concentrations may reduce acute alcohol cravings and consumption in the short term. This potential substitution effect has drawn both scientific interest and policy debate, as it raises questions about whether cannabis legalization shifts patterns of alcohol use at the population level.