Physiological, plasma beta-endorphin and cortisol responses to nasotracheal intubation were studied in 20 distressed infants of median age 0.3 days (range 0.1-23 days) randomized into groups given pethidine 1 mg/kg (n = 10) or alfentanil 20 micrograms/kg plus suxamethonium 1.5 mg/kg (n = 10) before intubation. All of the infants were given glycopyrrolate 3-5 micrograms/kg. Hypoxaemia during intubation was found in all 10 infants in the pethidine group and in 7 of 10 infants in the alfentanil-suxamethonium group, its duration being significantly longer in the pethidine group and being associated with the duration of the intubation procedure. Blood pressure increased, but not statistically significantly, in all except 2 patients in the alfentanil-suxamethonium group and bradycardia appeared in 1 patient in each group. Plasma beta-endorphin and cortisol values did not show any statistically significant intra-group or inter-group differences. Newborn infants suffer from hypoxaemia during intubation when awake more and therefore need adequate premedication before elective intubation. One alternative is the combination of glycopyrrolate, alfentanil and suxamethonium described here, although the ideal medication and dosage still remain to be defined.