Several acetogenins, characteristic of the Annonaceae, have been found to exhibit pesticidal and feeding-deterrent activities against a variety of pests and are undergoing commercial development as pesticides. The sensitizing potential of one of these plants, pawpaw, Asimina triloba Dunal, was examined in the current study. The potential of Fraction F020 (a pesticidal crude extract of pawpaw stem bark) to sensitize and elicit an allergic contact dermatitis response was determined by using a modified guinea pig maximization test (GPMT). Fraction F020 is a weak sensitizer and the active compound, asimicin, a trihydroxy-bistetrahydrofuran fatty acid gamma-lactone, is a weak irritant.