Lactobacillus acidophilus, or acidophilus for short, is one of the most useful organisms in your body. Acidophilus a beneficial bacteria, one of the organisms living in the stomach and the intestines which are necessary for the correct absorption and assimilation of nutrients, as well as for the defense of your digestive system against harmful organisms. Acidophilus or lactobacillus acidophilus is the most commonly used good or friendly bacteria. These bacteria inhabit the intestines and vagina and protect against the entrance and proliferation of harmful organisms that can cause diseases. Acidophilus may provide additional health benefits, including a boosted immune system, improved gastrointestinal function, and a decrease in the frequency of vaginal yeast infections. Acidophilus may also provides relief from indigestion and diarrhea.