The objective of this work is to provide knowledge about an exceptional case of pulmonary fibrosis related to chronic and high exposure to formaldehyde in a professor of medical anatomy and to review allergic dermatitis with the study of a doctor and a nursing assistant. They were diagnosed with allergic dermatitis to formaldehyde. Formaldehyde is used to manufacture a large number of industrial products such as urea and melamine phenolic resins, which have various applications in adhesives and binders, wood products such as cellulose pulp for making paper, plastic products, and paints for coatings and products for the textile industry. In other areas, including the clinical field, it is used directly in aqueous solution as a disinfectant, tissue preservative and biocide. Here, we report three cases of occupational disease caused by exposure to formaldehyde (one case of pulmonary fibrosis and two cases of allergic contact dermatitis). One of the individuals affected worked in a medical school and the other two are employed in university hospitals. The case of pulmonary fibrosis was caused by about 37 years' exposure to high ambient concentrations of formaldehyde in the workplace. To avoid or minimise cases such as those reported here, health and safety measures must be followed and specific health monitoring should be conducted of exposure to formaldehyde, which is highly sensitising and carcinogenic.