Abstract Introduction: Despite widespread use of cannabidiol (CBD), no lifelong toxicity study has been published to date. Caenorhabditis elegans is often used in preclinical lifelong toxicity studies, due to an estimated 60–80% of their genes having a human ortholog, and their short lifespan of *2–3 weeks. In this study, we examined both acute and long-term exposure studies of CBD at physiologically relevant concentrations. Materials and Methods: Acute toxicity was determined by treating day 1 adults with a wide range of CBD concentrations (0.4 lM to 4 mM) and assessing mortality and motility compared to control animals. Thermotolerance was examined by treating adult animals with CBD (0.4...