['Vomiting, large gastric residuals and abdominal distension are common in very immature infants on formula feeding. The present trial investigated whether a protein hydrolysate formula reduces the gastrointestinal transit time in preterm infants. Fifteen preterm infants (median gestational age 29 (24-32) wk, birthweight 1241 (660-1900) g, postnatal age 18 (5-54) d) on full enteral feeds (>150 ml/kg*d) were enrolled. It was hypothesized that the gastrointestinal transit time is at least 2 h shorter when protein hydrolysate formula is fed compared with standard preterm formula. In a randomized cross-over design study, each formula was fed for 5 d. On days 4 and 9 the gastrointestinal transit time was estimated using carmine red. The protein hydrolysate formula had a markedly shorter gastrointestinal transit time (9.8 h) than the standard formula (19 h) (p = 0.0022, two-sided Mann-Whitney U test).'] Does hydrolysed protein accelerate the gastrointestinal transport of formula in preterm infants?