In addition to measuring tobacco smoke analytes, there will be an increasing demand in the future to establish guidelines for testing the biological activity of tobacco smoke. Thus, testing methods have been identified which can provide valid data in terms of the cytotoxic and genotoxic potential of tobacco smoke. As a prerequisite, the tests performed in our laboratory included a battery of in vitro short term tests rather than animal experiments. In addition, our test results allow a quantitative evaluation in order to be able to compare different products. With regard to some biological effects of tobacco smoke known from the literature, an appropriate testing battery consisted of the following: The Ames microbial mutagenicity assay with TA 98 to assess genotoxicity of tobacco smoke condensate, a ciliate motility assay (with Tetrahymena vorax ) to assess ciliatoxicity of the gaseous phase or whole tobacco mainstream smoke, and the neutral red cytotoxicity assay using HEP-G2 human cell line. Besides that some other effects on mammalian cell cultures were evaluated by commercially available multi titer plate (MTP) assay kits. Some testing data of cigarette mainstream smoke will be presented to serve as examples for the routine application of these methods, including description of factors influencing the outcome of these tests.