A prospective study of the course of breast feeding was carried out in a group of 150 mothers. The reasons for terminating breast feeding before six months and the occurrence of transient lactational crises were recorded. 23% of the mothers gave up breast feeding because of lactational difficulties. 12% stopped for external reasons and 65% carried on beyond six months. 36% of mothers experienced one or more transient lactational crises, which were successfully overcome by proper breast feeding techniques in a few days.