Guinea pigs were exposed to kerosene aerosols or to smoke produced from kerosene under conditions approximating those in a kitchen. They were compared to controls exposed to saline aerosols or to atmospheric air. Both types of kerosene exposure engendered aortic plaques, resembling those seen in atherosclerosis, and changes in levels of blood lipids. The results suggest that chronic exposure to kerosene, a domestic fuel widely used in many countries, may have important toxic effects in addition to the pulmonary effects that have been reported by others.