Abstract Due to a lack of published pharmacokinetic (PK) and/or pharmacodynamic (PD) data, informed physician and patient decision-making surrounding appropriate dosing of cannabis for medical purposes is limited. This Phase 1, multiple-dose study evaluated the safety, tolerability, PK and PD of Spectrum Red softgels (2.5mg ∆9-tetrahydrocannabinol (THC) and <0.25mg cannabidiol (CBD)). Participants (n = 41) were randomized to one of five groups: 5 mg THC and 0.06 mg CBD daily (Treatment A), 10 mg THC and 0.12 mg CBD daily (Treatment B), 15 mg THC and 0.18 mg CBD daily (Treatment C), 20 mg THC and 0.24 mg CBD daily (Treatment D) or placebo....