National surveillance of herbal dietary supplement exposures: the poison control center experience

The purpose of this report is to characterize reports to poison control centers (PCCs) involving two widely used herbal dietary supplements (HDSs), Echinacea, and St. John's wort (SJW).

We purchased data from the American Association of Poison Control Center's (AAPCC) toxic exposure surveillance system (TESS(R)) on reports made to PCCs in 2001 involving Echinacea or SJW. Analyses were limited to those cases in which Echinacea or SJW were the only associated products, and in which these HDSs were deemed primary to observed adverse effects. Descriptive statistics were generated for selected demographic and exposure-related variables.

During 2001, PCCs were contacted regarding 406 exposures involving Echinacea and 356 exposures involving SJW. Most of the reported exposures for both HDSs occurred among children 5 years and younger, and the majority of exposures were coded as unintentional. For both HDSs, exposures among patients >/=20 years old were more likely to be associated with adverse effects. Intentional exposures accounted for 21% of SJW cases and 3% of Echinacea cases, with 13% of SJW exposures reported as 'suspected suicidal'.

TESS represents a potentially important means of assessing and characterizing HDS-related adverse effects. Detailed studies validating the clinical events and outcomes of a sample of exposures reported to TESS(R) might offer substantial insights into adverse events (AEs) that could be systematically studied with other, established pharmacoepidemiological study designs.