Your GI tract contains LOTS and LOTS of different species of bacteria, and even small amounts of yeast. Your gut likes VARIETY. Rotating different types of probiotics is recommended. Especially during times when life gets stressful, bad eating habits have crept back in, antibiotics have been used, or when alcohol has been consumed regularly or even occasionally. Hello, holiday season. Comment PB and I will send you the link to our Probiotic Bundle to make rotating probiotics simple and effective