Introduction: the use of cannabis has increased significantly over the last few decades. However, knowledge surrounding the simultaneous use of this substance and alcohol is scarce. Objective: to explore the prevalence, effects and risky situations related to the simultaneous use of cannabis and alcohol, with a focus on Mexico. Method: for this narrative review, a search was carried out in the PubMed database using the terms “alcohol”, “cannabis”, “marihuana”, “co-use” and “simultaneous use”. The relevant literature was selected and notable references were reviewed, focusing on alcohol and cannabis use disorders, consumption during pregnancy and before driving. Results: the prevalence of simultaneous alcohol and cannabis use has increased over the past few years, particularly among adolescents and young adults. This consumption pattern results in increased cognitive impairment, a higher number of negative consequences, a greater impact on embryonic development and a higher probability of risky driving compared to single-substance use. Discussion and conclusions: understanding this consumption pattern is essential for developing prevention and harm reduction strategies for vulnerable populations and risky situations. It is necessary to standardize the terms and methodologies used and carry out more studies focused on the prevalence, pharmacological and long-term effects of simultaneous alcohol and cannabis use with larger and more diverse samples, including the Mexican population.