NOW Respiratory Care Probiotic is a probiotic combination featuring L. acidophilus NCFM, which has been used in over 60 scientific studies. When used alone or in combination with B. lactis BI-04, NCFM has been shown to support a robust, but balanced, immune response to seasonal respiratory challenges, as well as to support an active lifestyle. NCFM can rapidly populate the intestine and adhere to the intestinal wall, which is helpful for use during and after temporary disruptions to intestinal microbiota.