CBD was neither symptomatically effective nor toxic, relative to placebo.
Link: Controlled Clinical Trial Of Cannabidiol In Huntington's Disease
Year: 1991
DOI: 10.1016/0091-3057(91)90386-G
No shown efficacy of cannabis for treatment of Huntington's Disease according to the results found in this study.
Oral CBD (10 mg/kg/day for 6 weeks) and placebo (sesame oil for 6 weeks)