Glutaraldehydel, (5-pentanedial) is a bifunctional aldehyde which is currently being used in dentistry as a pulpotomy medicament, dentin bonding mediator, sterilizing agent, and for various tissue preparation procedures. Its two, highly reactive terminal aldehyde groups rapidly and irreversibly react with proteins while reversibly reacting with DNA. Glutaraldehyde is used at a concentration of at least 2% in all of the dental applications mentioned. Toxicity of the compound in laboratory animals is unclear due to conflicting information, but strong irritation and skin sensitization have been reported. Irritation to the eyes, lungs, skin and gastric mucosa have been reported in humans. Mutagenicity information on glutaraldehyde is limited and available results are contradictory. Only one in vivo study has been reported. Therefore, the purpose of this study is to investigate the genotoxic potential of glutaraldehyde using five independent tests. These tests include: (1) the Ames Salmonella test; (2) an in vitro Chinese hamster ovary cell sister chromatid exchange assay; (3) an a in vivo Chinese hamster bone marrow cell sister chromatid exchange assay; (4) a mouse sperm morphology test; and (5) a mouse bone marrow micronucleus study. Because each test has strengths and weaknesses, a battery of carefully-selected in vitro and in vivo test systems will be used to evaluate the mutagenic potential of glutaraldehyde. It is believed that this series of genotoxic tests, taken collectively, will provide reliable data on the genetic effects, if any, of glutaraldehyde, and will help establish the risks or safety of its continued use in dentistry.