Abstract Liver safety concerns were raised in randomized controlled trials of cannabidiol (CBD) in patients with Lennox-Gastaut and Dravet syndromes, but the relevance of these concerns to healthy adults consuming CBD is unclear. The objective of this manuscript is to report on liver safety findings from healthy adults who received therapeutic daily doses of CBD for ~ 3.5 weeks and to investigate any correlation between transaminase elevations and baseline characteristics, pharmacogenetic, and pharmacokinetic data. Sixteen healthy adults were enrolled in a phase I, open-label, fixed single-sequence drug–drug interaction trial to investigate the effect of repeated dose administration of CBD (1,500 mg/day) on cytochrome P450...