PROJECT SUMMARY Sale of cannabis for recreational use is rapidly becoming legal across states in the US. While cannabis use policies typically contain marketing restrictions, including prohibitions on misleading marketing claims, there is limited research to inform operationalization of these policies, and these policies are rarely enforced. Cannabis products are often labeled based on “species” or cultivar (Indica, Sativa, or Hybrid). Notably, there is limited evidence that different species consistently have different profiles of chemical constituents. Despite this, cannabis is marketed directly to consumers with product labels “Indica”, “Sativa”, and “Hybrid”, and with corresponding marketing claims that the product has sedative (e.g., relaxation, sleepiness) or energizing (e.g., focus, productivity, physical activity) effects. Consumers also report experiencing sedative effects from Indica- labeled cannabis and energizing effects from Sativa-labeled cannabis. This may translate into unsafe use: our prior work has found consumers are more likely to report using Sativa-labeled (vs. Indica-labeled) cannabis before driving or going to work. Despite the potential for public health harm, there is no data demonstrating whether product perceptions, use expectancies, and subjective and objective acute effects of use vary by label or marketing claim. Research from other consumer domains, including tobacco, indicates that labeling and marketing can have powerful effects on product perceptions, use behavior, and use experience. Marketing and labeling for cannabis could similarly foster inaccurate product perceptions (e.g., regarding harm), expectancy effects (e.g., anticipating a product to increase focus) and lead to unsafe use (e.g., while driving). This undermines initiatives to promote safe use of cannabis and risks public health. To date, controlled research has not systematically evaluated how product labeling (Indica, Sativa, Hybrid) or associated marketing claims (sedative vs. energizing) affect use behavior, risk perception, or acute drug effects. The proposed research uses a large-scale content analysis of cannabis labeling and marketing (Aim 1), a randomized online experiment (Aim 2), and a placebo-controlled randomized laboratory experiment (Aim 3) to document the scope and effects of cannabis labeling (Indica, Sativa, Hybrid) and marketing claims (sedative, energizing). Ultimately, this work will provide evidence to inform cannabis marketing and labeling policies, which are necessary to protect public health.