Drugs that contain compounds called cannabinoids from the Marijuana plant don't increase the risk of serious side effects but are associated with an increase in some non-serious side effects, Canadian scientists report.

The researchers at McGill University in Montreal and the University of British Columbia (UBC) examined adverse events reported in 31 clinical studies of cannabinoid medications conducted between 1966 and 2007.

The adverse events were grouped as serious or non-serious. Serious adverse events included those that led to hospitalization, disability or death. Non-serious adverse events included dizziness and drowsiness.