Although biological/infectious risks are the most important in a medical biology laboratory, chemical risks should not be underestimated. Chemical products are used for analyses, and for disinfecting premises and equipment. Their toxicity imposes strict legislation, which is available to medical biologists in the French Labor Code, European legislation and Inrs (National Institute for Research and Safety) documentation. These sources are necessary because chemical risks are not taken into account by COFRAC (Comité français d'accréditation). The educational aim of this article is threefold: to identify the hazards and risks associated with the use of chemical products; to explain what to do in the event of an accident; and, finally, to provide information on prevention and protection.