There are an estimated 200,000 severe adverse drug errors (ADRs) in Canada each year, though it is estimated that 95% of ADRs are not reported. They cost the Canadian healthcare system between $13.7 and $17.7 billion each year and kill up to 22,000 Canadians each year. Over 5,000 of these are Canadian children. ADR Canada is working to prevent this. This article explains the role of genomics in the solution to adverse drug reactions.