Lactobacillus Acidophilus

March 21, 2017

Lactobacillus Acidophilus

Other name(s):

Lactobacillus acidophilus, Lactobacillus bulgaricus, acidophilus

General description

Lactobacilli are bacteria. They make lactic acid from the metabolic breakdown of carbohydrates. This is mainly the sugar lactose in milk.


Lactobacilli grow well in milk and milk products. They’re responsible for the "souring" of milk. Many different strains can be found in milk products. They can also be found in the intestinal tracts and vaginas of adults and in the intestinal tracts of formula-fed infants.

Lactobacilli are used commercially to make cheese and yogurt. Specifically, these are Lactobacillus bulgaricus.

Medically valid uses

L. acidophilus has been used to control certain types of diarrhea. It may be especially helpful for diarrhea due to oral antibiotics. These medicines destroy the normal flora of the intestine. L. acidophilus replenishes the intestine with a beneficial bacterium. This often stops diarrhea. It may also help keep vaginal yeast infections in check.

Animal research shows that L. acidophilus may increase the immune response to certain vaccines. 

A related species of Lactobacillus may control the growth of cancer cells. Research in this area is ongoing. 

Unsubstantiated claims

Please note that this section reports on claims that have not yet been substantiated through studies.

Over the last few years, L. acidophilus and bifidobacterium (another group of bacteria found in the intestine) have been recommended often. However, studies are still in progress.

For instance, L. acidophilus may improve immune function. It may also help treat lactose intolerance and restore normal intestinal flora. It may also reduce cholesterol levels and lower the risk of colon cancer. It may aid in preventing gastrointestinal ulcers. It may even help manage human papilloma virus (HPV) infections.

Dosing format

L. acidophilus comes as a powder, granule, or capsule form.

Pure cultures of L. acidophilus are available in health food stores. You should store them in light-resistant containers. Keep them away from excessive heat. Make sure to use them before the expiration date. Live-culture yogurt may also contain L. acidophilus.

Side effects, toxicity, and interactions

L. acidophilus doesn’t seem to cause any symptoms if you take too much of it.

Tell your healthcare provider about all medicines you take before using L. acidophilus. It may interact with corticosteroids, immune suppression medicines, and chemotherapy. You should also talk to your healthcare provider before taking it if you have a weakened immune system due to human immunodeficiency virus (HIV) or another condition.


March 21, 2017


Probiotics for Gastroinestinal Diseases. UpToDate.

Reviewed By:  

Poulson, Brittany, RD, CDE,Wilkins, Joanna, R.D., C.D.