We report a case of a nonatopic patient in whom exposure to Voacanga africana (VA) dust precipitated asthma. The patient was indirectly exposed to this dust by her husband, a chemist working in a pharmaceutical plant in which VA is used for the production of vinburnine, an alkaloid derivative. Vinburnine (Cervoxan) is widely used in conditions associated with cerebral circulatory insufficiency. Studies revealed the presence of immediate skin test reactivity to VA dust, and specific anti-VA antibodies were detected in the patient's serum by the reverse enzyme immunoassay technique. Bronchial challenge with a VA extract also resulted in an immediate asthmatic response without late reaction. These findings suggest a type I IgE-mediated immunologic mechanism as being responsible for the patient's respiratory symptoms. Unexposed persons did not exhibit reactivity to this seed with any of the tests referred to above. To the best of our knowledge, this is the first reported case of occupational asthma caused by VA seeds.