Other name(s):

Lactobacillus acidophilus, Lactobacillus bulgaricus, acidophilus

General description

Lactobacilli acidophilus are bacteria. They are also called L. acidophilus. They make lactic acid by breaking down carbohydrates. This is mainly done by breaking down the sugar lactose in milk.

Lactobacilli grow well in milk and foods made from milk. They’re responsible for the "souring" of milk. Many different strains can be found in milk foods. They can also be found in the intestinal tracts and vaginas of adults and in the intestinal tracts of babies fed with formula.

Some strains of Lactobacilli are used to make cheese and yogurt. These are Lactobacillus bulgaricus.

Medically valid uses

L. acidophilus has been used to control certain types of diarrhea. It may be helpful for diarrhea due to oral antibiotics. These medicines kill the normal flora of the intestine. Consuming L. acidophilus helps put good bacteria into the intestines. This often stops diarrhea. It may also help treat vaginal yeast infections.

Unsubstantiated claims

There may be benefits that have not yet been proven through research.

Over the last few years, L. acidophilus has been recommended often. But studies are still in progress.

For instance, L. acidophilus may improve immune function. Animal research shows that L. acidophilus may increase the immune response to certain vaccines. 

It may also help:

• Treat lactose intolerance

• Restore normal intestinal flora

• Reduce cholesterol levels

• Lower the risk of colon cancer

• Prevent gastrointestinal ulcers

• Help manage human papillomavirus (HPV) infection

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

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 high heat. Make sure to use them before the expiration date. Live-culture yogurt may also have L. acidophilus.

Side effects, toxicity, and interactions

L. acidophilus likely won't cause any symptoms if you take too much of it.

Talk with your healthcare provider before using L. acidophilus if you take any of these medicines:

• Corticosteroids

• Immune suppression medicines

• Chemotherapy medicines

You should also talk with your healthcare provider before taking it if you have a weakened immune system due to HIV or another condition.