Probiotics are live organisms thought to improve the microbial balance of the host. They are thought to reduce the risks of changes in gut flora related to antibiotic use and colonisation by pathogenic bacteria.
Probiotics have been shown to reduce antibiotic-associated diarrhoea in adults and children, in admitted and ambulatory patient settings, with different probiotic species, with lower or higher doses of probiotics and in studies at high or low risks of bias.
Probiotic use is a low-risk, low-cost useful intervention for people at a higher risk of antibiotic-associated diarrhoea. A post-hoc subgroup analysis showed probiotics are effective in trials with a C. difficile-associated diarrhoea baseline risk >5% (NNT = 12; moderate certainty evidence) but not in trials with a lower baseline risk. Unfortunately, there is not yet a prospective risk-prediction tool applicable to general practice settings.
Published data at this time does not show a difference in efficacy or tolerability with combinations versus a single probiotic.