A set of symptoms has been described during the past two decades that has been called the "sick building syndrome." These symptoms include eye, nose, and throat irritation; headache; mental fatigue; and respiratory distress. It is likely that the volatile organic compounds (VOCs) present in synthetic materials used in homes and office buildings contribute to these symptoms. However, there have been very few studies in which humans have been exposed to known amounts of VOCs under carefully controlled conditions. In this study, 14 subjects were exposed to a mixture of VOCs (25 mg/m3 total hydrocarbon) that is representative of what is found in new homes and office buildings. Because irritations of the nose and throat are symptoms often associated with the upper respiratory tract and may result from an inflammatory response in the upper airways, we used nasal lavage to monitor neutrophil (PMN) influx into the nasal passages following exposure to VOCs. There were statistically significant increases in PMNs, both immediately after a 4-h exposure to VOCs and 18 h later.