After many decades of prohibition, the US is undergoing a state-by-state liberalization of cannabis laws. Medical use of cannabis is now allowed in 23 states, and Colorado, Delaware, Washington (state), and Washington, DC, have all legalized the possession and recreational use of the drug.While the medical establishment doesn’t have a lot to say about the dose required for recreational activities, it does tend to care about medicinal uses. A new paper in JAMA this week suggests that in the majority of cases, the amount of psychoactive ingredients in the medical edibles is significantly less than claimed.The authors identified cannabis dispensaries in Los Angeles, San Francisco, and Seattle that sold cannabis baked goods, drinks, or candy with packaging labels that identified the amount of tetrahydrocannabinol (THC)—one of the primary active compounds in cannabis. After selecting three in each city, they purchased a total of 75 different edibles (from 47 different brands) and took them back to the lab to determine the actual amounts of THC in each. They also looked for cannabidiol (CBD), another psychoactive compound that some products provided an amount for (others didn’t).