Failure to identify tobacco- or heroin-exposed neonates is extensive owing to the limitations of current methods used to verify maternal drug use. Maternal self-reported drug history has been shown to be unreliable: many women who deny use during pregnancy exhibit drug metabolites in their urine. Maternal systematic urinalysis is hampered by the short elimination half-life of the drugs. This test is not suitable for validation of survey data since the quantification of drugs in urine only reflects exposure during the preceding 1-3 days and does not necessarily indicate the frequency in subjects who might deliberately abstain for several days before biomedical screenings. The same disadvantages are noted with the analysis of babies' meconium, or the amniotic fluids which are only a qualitative test at the moment of delivery. Hair analysis remedies the disadvantages of these currently available methods by exhibiting a wide window of detection and may provide information concerning the severity of gestational exposure. Hair samples were collected at time of delivery from 40 and 9 neonates whose mothers were known, by self-report, to be smokers and heroin users during the prenatal period, respectively. Hair was decontaminated in dichloromethane (37 degrees C, 15 min) and homogenizated in NaOH (1 M, 10 min, 90 degrees C). Nicotine and opiates were extracted in diethylether at pH 14, and in chloroform/isopropanol/n-heptane (50:17:33 v/v) at pH 9.2, respectively. After separation on a BP-5 capillary column, drugs were identified and quantified by GC/MS using selected ion monitoring. The ranges of measured concentrations were 0.15-11.80 and 0.61-3.47 ng/mg for nicotine and morphine, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)