It is a great challenge for practitioners not having internationally uniform guidelines available for the methodologies of microbiome testing and evaluating results. While on the internet there is a rapidly grow­ing amount of preclinical and clinical data describing clear disease associations in randomised controlled trials readily accessible to patients, guidelines for clinical decision-making algorithms at the bed­side are currently lacking. Our goal is to compare different microbiome testing methods and to shed light on the biological significance of the most frequently appearing parameters in the findings: diversity, phylogenetic and func­tional taxonomic groupings (e.g. the F/B ratio) and its clinical relevance. The clinical application must integrate the diagnostic and therapeutic approaches of several fields of expertise with completely new and dynamically developing molecular diagnostic and nutritional therapeu­tic guidelines. It is imperative for the specialised physician managing the patient's treatment to receive professional help from molecular biologists, microbiologists, and related professions when evaluating the findings and making a therapeutic decision. The microbiome is typically associated with the human body on the barrier surfaces of the alimentary canal, such as the mouth, gastrointestinal tract and the skin, etc., so it is essential to involve specialists and imaging disciplines as early as biopsy sampling and/or treatment. According to our recommendations, interdisciplinary teams similar to tumour boards are needed for the successful clinical application of the results.

The article reviews the epidemiology, etiology and diagnostics of persistent diarrhea in childhood, and then describes in detail the treatment options in detail. The most important in therapy is to ensure adequate rehydration, but special treatment is needed depending on what causes the persistent diar­rhea. Accurate diagnosis is essential for this. The author draws attention to the importance of nutrition therapy and prevention.

Iron deficiency anaemia (IDA) occurs in 2-5% of adult men and postmenopausal women in the developed world and is a common cause of referral to gastroenterologists. Gastrointestinal (GI) blood loss from colonic cancer or gastric cancer, and malabsorption in coeliac disease are the most important causes that need to be sought.