PURPOSE: Risk assessment for natural health products (NHPs) may not be evaluated similarly to therapeutic products by Health Canada in terms of notification of harms to consumers and health professionals. In this descriptive study, we evaluated risk communications (RCs) issued by Health Canada for NHPs and for therapeutic products, looking for differences in a number of variables.

METHODS: Risk communications issued by Health Canada in 2006 were independently evaluated by two investigators for whether the harm was actual or potential, for the seriousness and nature of harm, the origin of report, publication type, and degree of association. Disagreements were brought before a third reviewer for adjudication.

RESULTS: During the study period, Health Canada issued 42 RCs for each of NHPs and therapeutic products. Most (86%) NHP RCs were issued for potential harm from contamination and adulteration, whereas 69% of therapeutic product RCs were issued due to actual harms (p < 0.0001). Two deaths had been associated with NHP use, compared with 15 deaths associated with the use of therapeutic products (p = 0.0048). The degree of association between product and harm was higher among NHP RCs compared with that among therapeutic product RCs (p < 0.0001). All reports issued for NHPs originated from foreign sources or Health Canada, whereas 69% of therapeutic product RCs were issued by drug manufacturers.

CONCLUSIONS: We identified important differences in the RCs issued for NHPs versus those for therapeutic products. Standardized formats for RCs are recommended.