Doctor’s Best Fast Melt Immune Probiotic contains 2 strains of beneficial bacteria from Bifodan that can help reduce the number and duration of upper respiratory tract and gastrointestinal incidents. Clinical studies show that these probiotic strains, Lactobacillus rhamnosus GG and Bifidobacterium lactis BL-04, help promote a healthy immune system. Approximately 70% of the immune system resides in the intestinal tract. Fast Melt Immune Probiotic dissolves rapidly and helps restore the natural balance of good bacteria in the digestive tract. For easy on-the-go use Doctor’s Best Fast Melt Immune Probiotic dissolves rapidly on the tongue without water. Just one great-tasting stick pack provides the daily dosage.