Effect of Lactobacillus reuteri DSM 17938 in Infants with Functional Chronic Constipation and the Change of Intestinal Microbiome

INTERVENTION: Group A: L.reuteri 5drops x 2/day and Placebo of MO x 2/day x 4 weeks Group B: L.reuteri 5drops x 2/day and MO x 2/day x 4 weeks Group C:Placebo of L.reuteri 5drops x 2/day and MO x 2/day x 4 weeks CONDITION: Functional Chronic Constipation PRIMARY OUTCOME: Frequency of defecation SECONDARY OUTCOME: Status of defication, pain during defecation, bleeding during defecation, fecal microbiome INCLUSION CRITERIA: 1)Person who clears Rome IV criteria At least 2 or more have continued for 1 month or more from the following symptoms Defecation less than twice a week History of excessive stool retention Painful bowel movements Giant fecal lump in the rectum Huge stool history Following establishment of toilet habits the following criteria will also be added At least feces incontinence at least once a week (after defecation in the toilet) A huge chaotic mass that the toilet is clogged 2)The age must be 6 months or more and less than 6 years old 3)Being after the start of weaning food