The time of passage of the first stool was studied in 39 patients with Hirschsprung's disease and 2,471 normal neonates. Only 25.6% of the patients with Hirschsprung's disease passed their first stool by 24 hours with no aids to promote colonic evacuation, while 97.2% of 2,471 normal neonates passed their first stool within this period. About 10% of preterm and low-birth-weight neonates without Hirschsprung's disease passed their first stool after 24 hours, but the delay of meconium passege was remarkable in the patients with Hirschsprung's disease. In this study it was ascertained that failure to pass meconium within 24 hours after birth implies the possibility of Hirschsprung's disease, but it was erroneous that no delay in the first stool denies the possibility of Hirschsprung's disease. Patients with Hirschsprung's disease was divided into 5 groups by the length of aganglionic bowel, and the time of the first stool was studied in each 5 groups. The lack of positive correlation was recognized between the length of aganglionic bowel and the time of first stool. The time of the first meconium passage is not a useful diagnostic tool to estimate the length of aganglionic bowel.
