Study participants will continue to complete the daily online questionnaire throughout the 28 days of treatment and for 7 days post treatment. Participants will also be asked to complete a weekly questionnaire on gastrointestinal symptoms (Gastrointestinal Symptom Rating Scale) throughout the entire study. In addition, participants in each group will be asked to collect one stool sample at baseline, one stool sample during week 4 of treatment and an additional sample during the washout period. Stool samples will be analyzed and quantified for the probiotic bacteria and changes in the microbiota.