Abstract In a prospective randomized study three different feeding regimens after operation were compared in 74 babies with infantile hypertrophic pyloric stenosis: gradual regrading of feeds over 48 h (regimen J), rapid regrading of feeds over 16 h (regimen 2), and initial starvation followed by full normal feeds at 24 h (regimen 3). No significant difference between the treatment groups was found either in episodes of vomiting after operation (regimen 1, 2·9 episodes in 21 patients; regimen 2, 3·6 episodes in 28 patients; regimen 3, 3·6 episodes in 25 patients) or in the mean duration of postoperative hospital stay (regimen 1, 59·3 h; regimen 2, 47·8 h; regimen 3, 56·7 h). We conclude that vomiting following pyloromyotomy is self-limiting and independent of the timetable or composition of the postoperative dietary regimen.