A study of the effects of inhaled hair-spray was performed on 118 specific pathogen free male Wistar rats (71 test animals and 47 controls). Rats were exposed for 5 min, three times a day, five days per week, during one to eight weeks, in two plexiglas chambers, one for controls and one for test animals. The chambers were 20 1 in size, but only the noses of the animals were exposed to ambiant air or to a hair-spray aerosol polluted atmosphere. In the test chamber, the hair-spray was aerosolized for 30 s at the beginning of each exposure, using about 30 g of nebulized product. This hair-spray amount was high, although non-lethal (70% of DL0, 45% of DL50 and 26% of DL100). The hair-spray exposed rats exhibited significant modifications in the antixenic defence mechanisms of their respiratory system: diminished ciliary activity of the tracheal epithelium (-26%), increased number of harvested pulmonary macrophages (+52%), but decreased phagocytic ability of these cells (-8%). However we did not observe histologic differences in the respiratory system of exposed and control rats.