Low aromatic and dearomatized white spirits (deWS) are often considered less hazardous to health than 'standard' or aromatic white sprit (stdWS, 15-20% aromatics). However, data on health effects of deWS in humans are sparse and controlled exposure studies are lacking. The aim of this study was to compare deWS and stdWS with respect to irritation and inflammation. Six female and six male healthy volunteers were exposed on five occasions in balanced order to 100 or 300 mg m(-3) deWS (0.002% aromatics) or stdWS (19% aromatics), or to clean air, for 4 h at rest. Discomfort in the eyes, nose and throat and breathing difficulty were assessed by ratings on visual analogue scales. The only significant increases in ratings (compared to clean air) were seen for eye irritation at the high stdWS exposure and for solvent smell at all but the low deWS exposure. Excluding smell, all average ratings were at the lower end of the 0-100 mm scale, and did not exceed the verbal expression 'somewhat'. Ratings during stdWS exposure tended to be higher than during deWS exposure. No exposure-related effects on pulmonary function, nasal swelling, nasal airway resistance, breathing frequency, blinking frequency, plasma inflammatory markers (C-reactive protein, interleukin-6) or biochemical variables (sodium, potassium, amylase, creatine kinase, urate) were seen. In conclusion, stdWS appears to be slightly more irritating than deWS. This could, however, not be confirmed by objective measurements.