Objective To investigate the prevalence of pulmonary acariasis among the employees working on traditional Chinese medicinal materials and observe the effect of treatment. Methods History inquiry, detection of mites in sputum, blood examination for eosinophils and specific antibodies, x-ray chest film were carried out for 327 workers involving in traditional Chinese medicinal materials. Mites were found in sputum in 121 persons who were then treated with metronidazole, twice a day with a daily dosage of 0.8g for seven days as a course of treatment. Two courses were conducted with an interval of 7-10 day. Prevalence and morbidity in different groups of occupation, age, and sex were analyzed. Results The overall infection rate of mites in sputum was 37.0% (121/327) with an average morbidity of 12.5% (41/327). Among the four types of worker investigated, the highest infection rate (51.8%), and morbidity (18.6%) were in those working in transfer warehouse; the second highest infection rate (40.7%) and morbidity (15.7%) were in employees in factory of Chinese traditional medicine. Both groups showed a significant difference with others(?2inf=11.36,P0.05). After treatment with metronidazole, 88.4% showed negative in sputum examination for mites and the efficacy of the treatment for pulmonary acariasis was 92.3%. Conclusions Employees engaged in traditional Chinese medicinal materials are one of the groups at the highest risk of pulmonary acariasis. Metronidazole is effective in treating the infection.