A pharmaceutical composition containing several different bacteria including Streptococcus thermophilus, Lactobacilli and Bifidobacteria is disclosed. The bacteria are present in the composition at a total concentration of 1.times.10.sup.11 to 1.times.10.sup.13 per gram. Further, methods of using the pharmaceutical are disclosed which include treatment of a gastrointestinal disorder and hypercholestermia. Also a method for modulating a host's immune response is disclosed.