OptiBac Probiotics 'One week flat' has been created especially for those wishing to take a short-term course of good bacteria. It contains strains such as Lactobacillus casei Rosell-215, and is advised to be taken consecutively for 7 days. Suggested for daily use, each sachet provides 5 billion live microorganisms, guaranteed until end of expiry. The strains within 'One week flat', such as L. casei Rosell-215, are well-researched and proven to survive to reach the gut alive. This supplement is also gluten free and so may be suitable for those who suffer with bloating. Each pack contains 28 sachets. It is important to note that this supplement, unlike a small amount of live cultures products, does not require refrigeration, due to improvements in freeze drying techniques and the strains being naturally robust and able to survive harsher conditions. All OptiBac Probiotics strains are thoroughly researched and documented, so you can be confident you're getting a high quality supplement, which is proven to reach the gut alive.