There is evidence that newborn babies feel pain even at the lowest gestational ages when they can survive. Because sweet solutions such as sucrose, given orally, may relieve pain in neonates, we decided to compare the effects of two concentrations of glucose (normally used for intravenous infusions) and of breast milk in a randomized controlled trial in 120 babies requiring heel-prick tests. Glucose solutions and breast milk are readily available in the neonatal department. No other treatment was given. Our results strongly suggest that 1 ml of a 30% glucose solution given orally alleviates mild pain significantly and can be used for this purpose in newborns. Breast milk and 10% glucose did not have a similar effect.