The PI was ended her work in the hospital and no replacement was found.

Functional constipation (FC) is a common condition in childhood, with an estimated prevalence of 0.7% to 29%.The diagnosis and treatment of FC can be difficult tasks, and children are often referred to specialist services causing treatment to become expensive and time-consuming.The standard treatment based on osmotic laxatives (mainly PEG). The recovery rate is 50% to 60% after 1 year of treatment, with 50% of the children having relapse within 5 years. Studies in adults have established the effectiveness of some lactic acid bacteria in the treatment of chronic constipation.

Functional constipation (FC) is a common condition in childhood, with an estimated prevalence of 0.7% to 29%.The diagnosis and treatment of FC can be difficult tasks, and children are often referred to specialist services causing treatment to become expensive and time-consuming.The standard treatment based on osmotic laxatives (mainly PEG). The recovery rate is 50% to 60% after 1 year of treatment, with 50% of the children having relapse within 5 years. Studies in adults have established the effectiveness of some lactic acid bacteria in the treatment of chronic constipation.However, it is unclear whether similar effects occur in children. Lactobacilli and Bifidobacteria are the most studied species showing a high safety profile. Both are able to promote colonic peristalsis which could be beneficial for the treatment of constipation .Even though traditional treatment is well established and safe, high proportion of children need prolonged treatment for several months or even years. For many parents there is a concern regarding prolonged treatment with PEG .Lactobacilli, bifidobacteria and FOS (fructooligosaccharide) increase stool frequency and decrease consistency in healthy adults and therefore could prevent recurrence of constipation after PEG withdrawal .The principle investigator hypothesize that treatment with probiotics adjunct to PEG and several months thereafter could decrease the proportion of children needed permanent or prolonged treatment (>12 months) with PEG.

The importance of the study and its practical benefits:

Treatment with PEG for FC is well established and is considered safe. Despite that, a high proportion of children need prolonged treatment for several months or even years. For many parents there is a concern regarding prolonged treatment with PEG. Previous studies did not demonstrate efficacy of treatment with probiotics or prebiotics in FC. Neither of these studies assessed effectiveness probiotics/prebiotic products as adjunct to the traditional treatment (PEG) of FC in shortening its period.

A recently published studies including from Israel, demonstrated efficacy of Lactobacillus reuteri in irritable bowel syndrome, infantile colic and functional abdominal pain .Therefore, demonstration of positive effect of treatment with probiotic product in FC, could imply for potential use of this product in other functional gastrointestinal disorders among children.

Inclusion Criteria:

• Age 0.5 - 15 years
• Diagnosis of functional constipation according to Rome IV criteria

Exclusion Criteria:

• Children with chronic diseases which could cause constipation: Celiac disease, food allergy, Hypothyroidism, Inflammatory Bowel Disease, electrolytes disturbances, Cystic fibrosis, Hirschsprung disease, Neuropathic conditions (Spinal cord trauma, Neurofibromatosis, Tethered cord) or intestinal pseudo-obstruction.
• Prematurity (< 34 weeks)
• S/P intestinal surgery
• Children treated with medications associated with constipation.
• Existing malignancy
• Primary or secondary immunodeficiency