In this study, cannabis legalization in Canada was associated with increased rates of ED visits for cannabis poisoning in older adults. The largest increases occurred after edible cannabis became legally available for retail sale, a phenomenon similarly observed in Canadian children. Possible explanations include increases in accidental ingestion; ease of access; lack of age-specific dosing instructions; and absence of safe and effective treatment options for chronic pain, sleep disturbances, and behavioral and psychological symptoms of dementia. Older adults are at particularly high risk of adverse effects from cannabis due to age-related physiological changes, polypharmacy, drug interactions, and multimorbidity.