Oral Administration of Actitan-F in Paediatric Diarrhoea

Inclusion Criteria: * Children of either sex aged between 1-5 years (inclusive); * Diagnosis of chronic diarrhoea due to the following conditions: * Functional gastrointestinal disorder fulfilling Rome IV Criteria\* * or * Functional gastrointestinal disorder fulfilling modified Rome IV Criteria \*\* * or * Post-infectious diarrea with daily painless, recurrent passage of three or more large, unformed stools * Parents/legal guardians\*\*\* availability to fill on a daily basis the electronic daily diary by a smartphone/tablet. * Parents/legal guardians have given a written informed consent for participation in the investigation at the time of enrolment or before. The parent/legal guardian should also have agreed to bring the child for the visits scheduled in the protocol and to provide the requested information during the telephonic follow-up visit; * Parents/legal guardian able to understand the full nature and the purpose of the investigation, including possible risks and side effects, able to cooperate with the Investigator and to comply with the requirements of the entire investigation (ability to attend all the planned investigation visits according to the time limits included) based on Investigator's judgement; * Willingness not to make diet and lifestyle significant changes during the trial. * Rome IV criteria of functional diarrhoea (Neonate and Toddlers below 5 years), must include all of the following: * Daily painless, recurrent passage of four or more large, unformed stools * Symptoms last more than 4 weeks * Onset between 6 and 60 months of age * No failure-to-thrive if caloric intake is adequate \*\* Modified Rome IV criteria of functional diarrhoea (Neonate and Toddlers below 5 years), must include all of the following: * Daily painless, recurrent passage of three or more large, unformed stools * Symptoms last more than 2 weeks (Nelson Pediatric Texbook 21st Edition, Chronic diarrhea) * Onset between 6 and 60 months of age * No failure-to-thrive if caloric intake is adequate * These criteria have been modified in order to align the study to the functional diarrhoea condition in the real life. * Parent is the child's biological or adoptive parent. Legal guardian is defined as an individual who was authorized under applicable state or local law to consent on behalf of a child to general medical care, when general medical care includes participation in research. A guardian also meant an individual who was authorized to consent on behalf of a child to participate in research. Exclusion Criteria: * Carbohydrate malabsorption, diagnosed either clinically (2 weeks exclusion diet with resolution of symptoms) or with proper testing (breath test)\*; * Patients with any of the following chronic gastrointestinal disorders: inflammatory bowel disease, pancreatitis, chronic liver disease, eosinophilic oesophagitis, peptic ulcer disease, celiac disease, pseudo-obstruction, small bowel bacterial overgrowth, or Hirschsprung's disease * Significant chronic health condition requiring specialty care (e.g., lithiasis, ureteropelvic junction obstruction, sickle cell, cerebral palsy, hepatic, hematopoietic, renal, endocrine, or metabolic diseases) that could potentially impact the child's ability to participate or confound the results of the investigation; * Gastrointestinal blood loss; * Recurrent or unexplained fevers; * Developmental disabilities impairing ability to understand or communicate; * History of hypersensitivity or allergy to investigational product; * History of previous abdominal surgeries in the past 3 months; * Known hypersensitivity to any of the components (active ingredients or excipients) of the investigational product; * Conditions known to producing immunodeficiency (AIDS, other congenital immunodeficiency syndromes, drugs therapy with steroids, anticancer drugs, etc.); * Patients who have received any of the following treatments within the 2 weeks before the baseline visit: * Agents specially developed for achieving adsorbing properties, e.g. kaolin, pectin, bismuth subsalicylate; * Treatments that modify intestinal secretions, e.g. racecadotril; * Treatments that modify intestinal motility, e.g. opiates, anti-cholinergic agents; * Systemic Antibiotics; * Antiemetic agents. * Patients who have received probiotics and prebiotics within the 1 week before the baseline visit, unless they have been taken at stable dose (the use of probiotics and prebiotics in dairy food such as yoghurt, cheese, milk prior to the investigation is permitted); * Parents/legal guardians' refusal or inability to give written informed consent to participate in the investigation; * Parents/legal guardians who, in the opinion of the Investigator, are unable to fill up the electronic patient diary; * Patients who have participated in any other clinical trial in the last 3 months prior to the start of the investigation. * Applicable only for patients with Functional gastrointestinal disorder fulfilling Rome IV Criteria.