After a short overview of the history of probiotics, the author presents the development of human intestinal microflora based on the newest genetic data and the microbiological features of main probiotics. The indications of probiotic administration have been defined and extended in recent years. The author reviews significant results of probiotic treatment in some gastrointestinal diseases based on meta-analytical data. Probiotics are useful in preventing and treating diarrhoea caused by antibiotics and Clostridium difficile caused diarrhoea. In the treatment of Helicobacter pylori infection, preparations containing certain Lactobacillus,Bifidobacterium strains or Saccaromyces boulardii could enhance by 5–10% the rate of successful eradication and reduce the incidence and severity of the side effects. Some symptoms of irritable bowel syndrome and thus the quality of life can be improved by probiotics. Their beneficial effect in ulcerative colitis was proven, while in Crohn’s disease has not yet been defined. The use of probiotics is not included in guidelines, with the exception of the Maastricht IV/Florence consensus. For each disease it is advisable to use probiotics containing strains only with proven beneficial effect. The efficiency of preparations containing mixed strains has not yet been properly investigated. The author reviews the rare but potentially serious side effects of probiotics. In Hungary, there are many probiotic preparations available which can be purchased in pharmacies without prescription: their use is more empirical than evidence-based. The European Food Safety Authority has recently rejected claims for probiotics to be classed as medicines given the lack of convincing evidence on the effects of probiotics on human health and well-being. Clearly, further research is needed to collect evidence which could be incorporated into the international guidelines. Orv. Hetil., 2013, 154, 294–304.
