Epidiolex is 98% cbd and is used to treat epilepsy.
Here are the side effects from that trial
“The most frequently occurring side-effect (experienced by 40% of participants) was somnolence (i.e. drowsiness). Other side-effects, in order of prevalence, include: fatigue (26%), diarrhea (16%), decreased appetite (11%), and increased appetite (10%). Within the trial, there was one death due to SUDEP (sudden unexpected death in epilepsy), which was not deemed a result of Epidiolex use. Side-effects were mild or moderate in 80% of cases.”