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Scientific names: Lactobacillus acidophilus

Efficacy-safety rating:

ÒÒ...Ethno or other evidence of efficacy.

Safety rating:

...No safety concerns despite wide use.

What is it used for?

Traditional/Ethnobotanical uses

For several decades, health and nutritional benefits have been claimed for products containing Lactobacillus cultures. The topical or intravaginal application of yogurt products has been reported to control yeast and bacterial infections.

Replenish normal bacterial flora

L. acidophilus has been referred to as a probiotic, defined as microorganisms that have a beneficial effect on the host by improving the properties of the indigenous microflora. Products containing live cultures have been investigated for their ability to compete with pathogens in the microenvironment, thereby permitting the reestablishment of normal bacterial flora. Lactobacillus has long been considered to be a component of the protective flora in the vagina. Recently, Lactobacillus species that produce hydrogen peroxide have been found in normal vaginal flora. Consequently, the therapeutic benefits of Lactobacillus products have been investigated in women with vaginal and urinary tract infections. Its value in treating lower urinary tract infections remains unclear. Acidophilus has also been used to treat sore mouth caused by Candida infections. While some clinical studies are positive, more studies are needed to determine the exact therapeutic benefits of acidophilus.

GI uses

L. acidophilus is normally found in the human alimentary tract. Consequently, the oral administration of products containing L. acidophilus may be useful in the management of a variety of conditions associated with altered GI flora. Their beneficial effects may be related to the ability to suppress the growth of pathogens. Acidophilus also has been reported by laboratory findings to suppress the growth of C. pylori, implicated in acid-peptic disease. More clinical trials are necessary to validate these findings. The ingestion of yogurt products has been associated with decreases in the concentration of several fecal enzymes that have the capacity to convert procarcinogens to carginogens in the colon. This suggests that the consumption of Lactobacillus-containing products may have beneficial effects, although no further data are available to support this hypothesis.

Antibiotic-induced diarrhea

The ingestion of Lactobacillus preparations has been recommended to reduce the symptoms of antibiotic-induced diarrhea. Some clinical studies show that Lactobacillus-containing products help reduce the incidence of diarrhea, nausea, cramping, flatulence, and yeast superinfection with patients on antibiotics. Yet to date, no consensus has been reached regarding the effectiveness for this use. Acidophilus did not prevent travelers diarrhea in another clinical study.

Cholesterol control

Other reports have indicated that the ingestion of acidophilus-containing products can reduce serum cholesterol levels. Acidophilus bacteria have the ability to assimilate cholesterol. However, conflicting results of clinical trials remain concerning Lactobacillus species-effect on serum cholesterol levels.

Lactose intolerance

Acidophilus milk has been used to treat patients with lactose intolerance, although controversy remains regarding its effectiveness on lactose digestion.

What is the recommended dosage?

Similar to yogurt, used as a food.

How safe is it?


Complete avoidance of L. acidophilus in children with short-bowel syndrome may help prevent episodes of D-lactic acidosis.


Information regarding safety and efficacy in pregnancy and lactation is lacking.


None well documented.

Side Effects

L. acidophilus is generally considered safe, as it is normally found in the human alimentary tract. However, in patients with abnormal heart valves who have recently experienced dental manipulation, endocarditis caused by Lactobacillus species has been reported.


No data.


  1. Aciduphilus. Review of Natural Products. factsandcomparisons4.0 [online]. 2004. Available from Wolters Kluwer Health, Inc. Accessed April 16, 2007.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.