Drug screening of breast milk in a clinical toxicology laboratory is reported. Findings from three cases include cocaine, ethylbenzoylecgonine (cocaethylene), ethanol, oxycodone, codeine, and nicotine. We believe this to be the first report of ethylbenzoylecgonine in human breast milk. One other specimen submitted for analysis was screened with negative results. Screening and confirmation procedures adapted for use with breast milk are described. Finally, the potential for cocaine intoxication from mother to baby is discussed. Estimates of infant blood cocaine concentration are given which may increase awareness of the need to monitor milk and blood cocaine concentrations in the infant when the situation warrants.