Formaldehyde or formalin is indispensable not only as a preservative but also as a disinfectant of cadavers for gross anatomy. It has recently attracted a great deal of attention as a health hazard for students and lecturers. To reduce the concentration of formaldehyde gas (FAG), we improved a novel local ventilation system of the push-pull type. This is the first report dealing with the effects of this ventilation system on the health of students before (over 1 ppm) and after (0.1 ppm) the installation. The percentages of students with lacrymal symptoms or airway irritation were reduced to a third of what they were before the installation. In particular, the number of those with continuously strong symptoms was reduced to a sixth of the pre-installation levels. This local ventilation system draws in fresh air from outside, and directs it to the breathing zone of the students, effectively reducing their symptoms.