Lactobacillus plantarum/rhamnosus/salivarius contains three probiotic strains that are particularly hardy. It may be appropriate for individuals who do not derive benefit from less hardy strains, such as L. acidophilus. Members of the genus Lactobacillus take up residence primarily in the wall of the small intestine, where they provide many functions, including normalization of pH, promotion of digestive function, and stimulation of immune response.*

Lactobacillus plantarum was originally isolated from sourdough bread, and has traditionally been used as a culture for fermenting bread and cabbage. L. plantarum is resistant to gastric acids and inhabits the small intestine when ingested. It produces lactic acid and bacteriocins.
L. plantarum has very high lactase activity, and it can deliver and release lactase throughout the stomach and small intestine, facilitating the digestion of lactose.

In Asia, Lactobacillus salivarius has been used as a supplement in functional foods and probiotic drinks. L. salivarius was originally isolated from the intestinal tract of humans, and it can also be found in dairy products and vegetable matter. It produces lactic acid and bacteriocins, and has moderate lactase activity.

Lactobacillus rhamnosus was originally isolated from the human intestinal tract. It has been shown to support the activity of both white blood cells and lymphocytic natural killer cells.* It is a good releaser of lactase throughout the stomach and small intestine. It also sometimes occurs in the large intestine, where it can create favorable conditions for the implantation of bifidobacteria.