ABSTRACT
Fourty male and female albino rats were housed in dissecting room of Pathology Department for 10 weeks to determine histopathological alterations in their internal organs resulting from exposure to occupational concentration of formaldehyde vapour [4.5 ppm]. Definite changes were induced in the liver [up to focal necrosis], kidney [focal periglomerular fibrosis], lungs [generalized congestion with epithelial hyperplasia and pseudostratification of bronchioles] and the testis showed focal hypospermatogenic tubules. These toxic changes nescessitate fulfillment of strict measures for reducing concentration of formaldehyde vapour in medical laboratories to protect medical and paramedical personnel, particularly those with hepatic, renal or pulmonary troubles