摘要:Background: Approximately 70% of all newbormns in South Korea are fed a commercial formula as their sole source of nutrition or as a supplement to breast milk. It is common for many formula-fed infants to be switched from one formula to another because of perceived abnormalities in stooling pattermns (too much/too lttle, too hard/too loose). Also, probiotics may have been recommended by a clinician or practitioner when there is thought to be a problem with the babies stool based on many reports. Aims: The primary objective of this study was to determine whether probiotic (nLp-nF1) exposure during the first 6 months of life is safe. The secondary objective was to assess if nF1 exposure correlated with changes in formula-fed infants’stool characteristics. Result: We recruited 49 healthy formula- fed infants aged 0-6 months from Bundang Cha Medical Center. Infants were given a 14-day supply of probiotics (nfl: Lactobacillus plantarum 2.5 X 1010/g/pack, 2 pack/day). The overall rate of stool change after probiotics is 83% (41/49). Among them, 75.6% (31/41) participants answered fairly about the change of stool characteristics. The significant change of stool frequency, stool color and flatulence after probiotics intervention was reported. The number of infants who defecated once daily was increased from 53% (26 of 49) to 77.5% (38 of 49) (P-=0.075). Mustard yellow colored feces increased from 22 to 40 (p=0.018). Only 9 out of 20 infants with flatulence (>3 times) showed persistence of symptoms after probiotics (ρ<0.001). After taking probiotics, Bristol Stool Scale 4-5 stool was reported from 23 to 37(p=0.018)..