The aim of this investigation was to determine whether nicotine exposure (1 mg/kg body mass/d) during pregnancy and lactation contributes to the rupturing of alveolar septa in the lungs ofneonatal rats. These rats received nicotine only via the placenta and mother's milk. The results show that maternal nicotine exposure interferes with elastic tissue formation. It also interferes with alveoli formation and causes the development of emphysema-like lesions. It is therefore suggested that maternal nicotine intake frolll smoking during pregnancy and lactation may interfere with lung developlllent and maturation to an extent that increases susceptibility to emphysema.