A survey was made on workers handling powdered drugs in a pharmaceutical factory. In this factory, two kinds of anti-inflammatory enzyme (bromelain and trypsin), one anti-inflammatory agent (flufenamic acid), one antispasmodic (flopropion) and two kinds of antibiotics (ampicillin and cephalexin) are mainly produced. Twenty four workers were examined by interviews and checked by Cornell Medical Index, and 18 of them complained of respiratory symptoms. These 18 workers were physically examined by skin scratch tests, pulmonary function tests and serum immunological tests. Among 24 workers, 9 handled powdered drugs (A group), 5 handled the same in the past and had already been transferred to other sections for their symptoms (B group), 3 engaged in the process of capsul-filling (C group) and 7 handled several times occasionally during one year (D group). Their average months spent in handling powdered drugs were, in the case of anti-inflammatory enzyme, A group 53.2, B group 66.2, and in the case of antibiotics, 5 workers in A group 24.0, 2 workers in B group 7.0, 3 workers in C group 25.7. Twenty workers complained of symptoms which were mainly irritation of mucosa including the respiratory system and itching of the skin while they were working, and accelerated nasal discharge, urticaria and asthma after working. Group A and group B were higher than group D in the rate of respiratory complaints in C.M.I. (p less than 0.001). Fourteen workers pointed out anti-inflammatory enzyme as a cause of main symptoms, 7 workers flufenamic acid, 3 workers flopropion, 4 workers antibiotics. Three workers who had past history of asthma or articular rheumatism had been transferred to other sections. Of 18 workers who were physically examined, 11 workers showed positive reactions to skin scratch tests with handling drugs. On 8 workers of them, some kinds of drugs which were pointed out as drugs causing main symptoms reacted positively. Numbers of workers with increased immunoglobin values were, IgE 3, IgM 2, IgA 4, IgM 2. Two workers showed decreased FVC and FEV (1.0 sec.) values in pulmonary function tests. The causes of the occupational allergic reaction in this factory are guessed as follows: 1) control of powdered materials was incomplete in the process of production, 2) various kinds of sensitizing drugs were handled by the same workers.