Hair samples were collected at the time of delivery from 63 neonates whose mothers were known to be heroin (9 cases), nicotine (40 cases), benzodiazepines (11 cases), cocaine (2 cases) and amphetamine (1 case) users. In all cases, the corresponding drug was found in neonatal hair from the infants, with concentrations in the range 0.61-3.47 ng/mg (morphine), 0.15-11.80 ng/mg (nicotine), 3.36-17.55 ng/mg (diazepam), 0.78-31.83 ng/mg (oxazepam), 0.71-2.47 ng/mg (benzoylecgonine), and 1.21 ng/mg (amphetamine). A significant correlation (P < 0.001) was established between nicotine concentration in the hair of the neonates, and in the hair of their mother.