The role of sesquiterpene lactones in contact hypersensitivity to some North and South American species of feverfew (Parthenium-Compositae).

Sixteen taxa of the genus Parthenium from North and South America and 20 sesquiterpene lactones derived from plants of the Compositae family were used for patch testing six volunteers who were known to be contact sensitive to plants and lactones of this family. The patterns of cross-sensitivity and structure-activity relationships of the allergenic lactones are evaluated and the clinical and ecological relevance is discussed.