There is a theoretical concern that probiotic strains may inhibit each other when given as a mixture. But in vitro studies have proved that a probiotic mixture is more effective at inhibiting pathogens than its component species given alone when tested at approximately equal concentrations .
There were no adverse effects of the intervention in this study. Probiotics are classified as generally regarded as safe (GRAS) by the Food and Agriculture Organization of the United Nations (FAO)/WHO. Studies in children have also found probiotics to be safe and beneficial .