The potential harmful effects of glutaraldehyde on human health are well known, and in recent years various new substitutes for this compound have been proposed for the disinfection and thorough sterilization of medical instruments. Nevertheless, glutaraldehyde is still widely used in hospital environments. In order to evaluate environmental contamination by glutaraldehyde vapours, the rooms of a hospital out-patient department of digestive endoscopy were monitored in 2005; a total of 52 samples were taken. The mean environmental concentration of glutaraldehyde was 3.7+/-7.4 microg/m(3). The number of efficacious air exchanges per hour was 6.3 v/h in all of the environments monitored. The study revealed that, in a hospital setting, adequate structural and functional planning, combined with responsible management on the part of the personnel and constant careful checking of the results obtained can minimize the risk of occupational exposure to glutaraldehyde.