Pain is subjective and can be quantitated in others only through cognitive cooperation between the sufferer and the observer. The newborn infant can neither describe pain nor remember it later in life. Thus, strictly speaking, we will never know if a pain experience can occur in the newborn period. However, many observations suggest that a nociceptive function exists at birth: (1) the neuronal pathways and transmitter systems required for pain conduction in adults seem to be present already during fetal life: (2) noxious stimulation of the newborn leads to behavioural responses and stress-related biochemical changes, and (3) the use of anaesthetic and analgesic drugs may improve the clinical outcome following surgery. The main features of the pharmacokinetics in the newborn period of both peripherally and centrally acting analgesics are now relatively well known and at least the short-term side effects are predictable and generally avoidable. Even if long-term adverse drug effects due to impaired imprinting have been suggested it appears that nociceptive stimuli in the newborn should be considered being disadvantageous to the patient. If they cannot be avoided, they should be treated.