A prospective study is needed to clarify the nature and extent of the influence of smoking on lactation and this study should be carried out jointly by obstetricians perinatologists pediatricians and epidemiologists. Incomplete data indicates that women who smoke frequently experience insufficient milk production and nurse for shorter periods of time than nonsmoking mothers. Animal studies also point to a relationship between nicotine and reduced milk production. A table from the Ontario Perinatal Mortality study shows that at the time of discharge from the hospital the % of new mothers who breast-feed is 51.6 for nonsmokers 44.0 for those who smoke less than a pack a day and 37.4 for those smoking more than a pack a day. The extent to which non-breast feeding was due to preference versus the result of an inability to breast-feed was not determined. A prospective study should seek to determine 1) if women quit smoking would they be more successful in nursing; 2) if women stopped smoking during the last three months and during the nursing period would milk production be adequate; 3) to what extent are the low nursing rates among smokers due to their inability to nurse; and 4) whether nicotine in the milk produces fretfulness in babies.