The harmful effects of passive smoking (PSE) start early in intrauterine life and comprise direct toxic effects of components of tobaccos smoke on the fetus as well as indirect effects by impeding the normal nutrition of the growing child over effects on the placenta. Consequences are diminished birthweight, and increased perinatal mortality. The sudden infant death syndrome is associated with PSE as are increased incidence of respiratory illnesses in early childhood. Increased bronchial responsiveness, increased asthma prevalence, delayed lung growth and increased incidence of chronic respiratory symptoms later in childhood may well put these children at increased risk for developing chronic obstructive pulmonary disease in their later life.