We performed a cross-sectional study to detect occupational asthma (OA) in 63 subjects occupationally exposed to herbal and fruit tea dust and in 63 corresponding controls. The evaluation included a questionnaire, skin prick tests to workplace and common inhalant allergens, spirometry, and histamine challenge test. The evaluation of the work-relatedness of asthma in the exposed workers was based on serial peak expiratory flow rate (PEFR) measurements and bronchoprovocation tests. We found a higher prevalence of respiratory symptoms in the exposed workers, whereas spirometric parameters were significantly lower. The prevalence of sensitisation to allergens and of bronchial hyperresponsivenss (BHR) did not differ significantly between the groups. The prevalence of asthma was also similar in both groups (8.0 %