The purpose of a study published in Pediatric Gastroenterology, Hepatology & Nutrition was to evaluate the correlation between colon transit time (CTT) test value and initial maintenance dose of polyethylene glycol (PEG) 4000 or lactulose. This study enrolled 190 children with chronic functional constipation, based on exclusion criteria using the CTT test, defecation diary, and clinical chart. CTT test was performed with prior disimpaction; laxative dose for maintenance was determined on the basis of defecation diary and clinical chart. The results showed that the overall group median value and interquartile range of the CTT test was 43.8 (31.8) hours. The average PEG 4000 dose for maintenance in the overall group was 0.68±0.18 g/kg/day. Meanwhile, according to age, the doses were 0.73±0.16 g/kg/day for children<8 years; 0.53±0.12 g/kg/day for children between 8 and <12 years; and 0.36±0.05 g/kg/day for children between 12 and 15 years. The doses of lactulose were 1.99±0.43 mL/kg/day for children <8 years or 1.26±0.25 mL/kg/day for children between 8 and <12 years. On the other hand, there was no significant correlation between CTT test value and initial dose of laxative, irrespective of the subgroup (encopresis, abnormal CTT test subtype) for either laxative. Even in the largest group, the correlation was weak. Furthermore, within the abnormal transit group, subgroup correlation was weak. From the findings, it was concluded that CTT test value cannot predict the initial maintenance dose of PEG 4000 or lactulose with linear correlation.