Researchers analyzed data from more than six million people to examine the relationship between proximity to a cannabis store and the number of cannabis-related emergency room visits. They found that neighborhoods with multiple cannabis stores in small areas experience higher numbers of emergency room visits compared to areas that are farther away from these stores. This effect was strongest just where stores clustered in higher densities. The results suggest that the density of cannabis stores has a significant impact on community health, specifically on the increased number of acute health problems requiring an emergency room visit. Thus, the study highlights the need to consider the public health impacts of the concentration of these stores.