["Addiction, Volume 121, Issue 5, Page 1262-1271, May 2026. ", "\nAbstract\n\nBackground and aims\nWhile half of the states in the United States of America (USA) have approved statewide retail sales of cannabis, local governments retain the authority to opt in or out of authorizing storefront recreational cannabis retailers. This study aimed to examine local‐level associations between the authorization of storefront recreational cannabis retailers and cannabis‐related healthcare encounters in California, USA.\n\n\nDesign\nA secondary data analysis of cannabis‐related healthcare encounters across 482 cities in California from 2010 to 2020. A spatial difference‐in‐differences model was employed at the city‐quarter level to assess both intracity and intercity associations, controlling for time‐varying city‐level policies and sociodemographic factors while accounting for spatial influence over neighboring cities.\n\n\nSetting\nCalifornia, USA.\n\n\nParticipants\nAll California residents from 2010 to 2020.\n\n\nMeasurements\nThree cannabis‐related healthcare encounter outcomes were assessed: (1) population‐adjusted emergency department visits, (2) population‐adjusted inpatient discharges, and (3) a binary indicator of any calls to poison centers. The primary policy variable was whether a city authorized storefront recreational cannabis retailers.\n\n\nFindings\nNo statistically significant intracity association was found between the authorization of storefront recreational cannabis retailers and rate of emergency visits [−0.14 percentage points; 95% confidence interval (CI) = −18.24 to 17.97; P = 0.988], rate of inpatient discharges (−6.11 percentage points; 95% CI = −17.58 to 5.36; P = 0.297) or probability of any poison center calls (−2.58 percentage points; 95% CI = −6.18 to 1.02; P = 0.161). For intercity associations, authorizing storefront recreational cannabis retailers was associated with a 6.75 percentage point decrease (95% CI = −12.46 to −1.03; P = 0.021) in the probability of any poison center calls in neighboring cities, suggesting that local cannabis policies may have influence extending beyond their immediate jurisdictions.\n\n\nConclusions\nIn California, USA, the local authorization of storefront recreational cannabis retailers appears to be associated with a reduction in cannabis‐related poison center calls in neighboring cities rather than within the policy‐implementing cities.\n\n"]