Formaldehyde (FA) is commonly used in cadaver fixation for years. FA vapors are released during the dissection process and macroscopic study of preserved anatomical pieces, raising their concentration in the Anatomy laboratory, causing greater exposure for students and teachers. Therefore, the objective of this study was to investigate toxic reactions in 37 students, through a questionnaire, produced by exposure to FA used for preservation of cadaveric material used in Anatomy, Morphofunctional Department, Faculdades Integradas de Patos (FIP), Brazil. Of the 37 interviewees, 26 (70.3%) were affected by the unpleasant and irritating smell of FA, 10 (27%) had no problems, and 1 (2.7%) did not tolerate an irritation produced by FA, ​​not participating in the laboratory practical classes. Exposure to FA was followed by several symptoms: excessive lacrimation (54%), itchy eyes (48.5%), redness of the eyes (40.6%), coryza or congested nose (35.2%) and respiratory distress (29.7%), with persistent symptoms during the permanence in the laboratory for 32.5% of the students. All students wear a lab coat for individual protection. However, only 8% used mascara and did not wear glasses, increasing the risk of contamination. Medical schools should encourage the use of Personal Protective Equipment (PPE) for the manipulation of FA, ensuring the protection of students and teachers in the Anatomy laboratory. Besides finding alternatives for the replacement of FA in the conservation of corpses.