For many individuals with Tourette syndrome (TS), available medications do not help with their symptoms, or cause significant side effects. Two small controlled trials have investigated the effect of oral delta-9-tetrahydrocannabinol (THC), a principal psychoactive ingredient of cannabis, in TS patients. While these trials have shown promising results, the effect sizes were not as large and consistent as those reported by patients with regards to inhaled cannabis (smoked or vaporized). Indeed, based on anecdotal evidence, patients have much greater improvement in their symptoms using inhaled cannabis than using cannabinoid pharmaceuticals. However, there have been no controlled trials of inhaled medical cannabis for TS to date. Furthermore, various medical cannabis products are authorized in Canada with different contents of THC and cannabidiol (CBD), another primary cannabinoid. No data exists regarding the dosing, efficacy and safety of these products in the treatment of TS. To gather such data, a double-blind, randomized, crossover pilot trial will be conducted to compare the efficacy and safety of three vaporized medical cannabis products with different THC and CBD contents, as well as placebo, in adults with TS. As well, the PK/PD profile of THC and CBD of the products will be assessed and correlated with tic symptoms