The Tradescantia-Micronucleus (Trad-MCN) test is a simple short-term bioassay for various gaseous and liquid forms of chemical agents, and physical agents such as radiation. 140 agents, directly or indirectly related to human health, were screened for their mutagenicity. Plant cuttings of young inflorescences, in which the pollen mother cells undergo various stages of meiosis, were maintained in nutrient solution for experimentation. Treatments were made either by absorption of the soluble agents through the stem, by diffusion of gaseous agents through the leaves and buds, by exposure to internal/external radiation or by in situ exposure to air pollutants. Micronuclei formed from damaged chromosomes served as the indicators of mutagenicity. Results of 140 agents tested are listed in 9 different categories. (1) Carcinogens/mutagens, (2) common beverages, (3) common chemicals, (4) drugs, (5) pesticides, (6) common household chemicals, (7) radiation and radioisotopes, (8) in situ monitoring, (9) complex environmental mixtures. Out of 140 agents tested, 52 showed positive, 20 showed borderline positive responses and 5 showed strong toxicity. Test results of 41 agents in the present study showed 67% congruity with Ames test results found in the literature.