Since 1990, the issue of whether the prophylactic administration of IM phytomenadione [vitamin K] to neonates to prevent vitamin K deficiency-related bleeding increases the risk of childhood cancer has remained unresolved. In 1992, Golding et al. reported a possible doubling of the risk of childhood cancer associated with neonatal IM phytomenadione administration.*However, other subsequently published studies failed to confirm the increased risk. Four new studies investigating the potential link have now been published in the latest issue of theBMJ. The results of 2 of these studies are largely reassuring, whereas the results of the other 2 studies are concerning.