7 subjects, each giving a history of scaly or vesicular dermatitis in light-exposed areas after going for strolls to the park, the forest or the country during warm weather, were evaluated. Patch testing was carried out with Frullania dilatata and Frullania tamarisci as well as with 2 common members of the Compositae and to alantolactone and the sesquiterpene lactone mix. All the patients were positive to F. dilatata, 3 reacted to F. tamarisci as well, and 2 to florists' chrysanthemum. All of them except 1 gave positive responses to the sesquiterpene lactone mix, but only 3 reacted to alantolactone. Airborne contact dermatitis from these species of Frullania was considered to be the cause of their eczema. Patch testing with the sesquiterpene lactone mix seems to be a good screen for Frullania sensitivity; however, a variable pattern of response to these sesquiterpene-lactone-containing materials was observed, suggesting individual immunologic responses to them.