The acute toxicity and the genotoxicity of four colored smokes were studied by an in vitro method based on the exposure of human bronchial epithelial cell cultures to the smokes. All smoke formulations consisted of the oxidizer fuel mixture (potassium chlorate/lactose), talcum and the following dyes: 1,4-dihydroxy anthraquinone (orange), 1-(p-tolylamino)-4-hydroxy anthraquinone (violet), 1-methylamino anthraquinone (red) and 4,4'-m ethylidyne-bis-3-methyl-1-phenyl-2-pyrazolin-5-one (yellow). The experiments were carried out in a laboratory scale chamber and in a large container. The toxicity was compared to that of hexachloroethane (HC)-based reference smoke with known toxicity. All the colored smokes displayed acute toxicity. The order of toxicity in the laboratory scale tests was orange > violet approximate to red > HC > yellow and in the container tests orange > violet approximate to yellow > red. The orange smoke appeared genotoxic in all the tests. With the yellow and the violet smokes, the genotoxicity could not be totally excluded. The red smoke showed evidence of weak genotoxicity only in one test series at the highest concentration level.