Lactobacillus acidophilus, or L. acidophilus, is a commonly known probiotic supplement which can be taken in pill, tablet, capsule, liquid or powder form.
It is frequently added to dairy products to impart probiotic properties to the food product. In Latin, the name literally means “acid-loving milk bacterium”, and that is precisely what it is.
This probiotic is found naturally in the body and lactobacillus acidophilus side effects are rare. Continue reading to learn more about the safety instructions for taking Acidophilus supplements.



- Supports a healthy immune system & microflora
- Promotes digestion & nutrient absoprtion
- Combats pathogenic bacteria; Improves metabolism
Acidophilus Overview
Related Topics
- What are Probiotics?
- Probiotic Benefits
- Best Probiotic Strains
- Probiotic Side Effects
- Probiotic Supplements
- Probiotic Foods
- Best Probiotic Yogurt
- Probiotics for Children
- Probiotics for Women
- Yeast Infections
- What are Prebotics?
- Lactobacillus Acidophilus
- Lactobacillus Bulgaricus
- Lactobacillus Rhamnosus
- Bifidobacterium Bifidum
- Bifidobacterium Infantis
- Bifidus Regularis
In our bodies, one way acidophilus works as a probiotic is by converting sugars into other chemical compounds like lactic acid and hydrogen peroxide.
By creating a highly acidic environment within the human GI tract, it becomes an unfriendly environment for pathogenic (unhealthy) bacteria to set up house.
Many people use acidophilus as part of their daily health regimen because it not only works to restore and maintain a beneficial balance of microflora in our gut, but also promotes better immune function.
It can be used to treat certain acute problems like diarrhea and vaginal candidiasis. Though most people experience no side effects whatsoever when supplementing with acidophilus probiotics, there are some minor side effects which are known and a few which are more rare, but serious.
Positive Effects
Probiotics are bacteria which, when introduced to the body, colonize and create a beneficial effect on the system of the person taking them.
Bacteria work specifically by colonizing in mass quantities; in fact, one way probiotics use to eradicate pathogenic bacteria from the GI tract is via a process called competitive exclusion.
By out-competing the harmful organisms, acidophilus (along with other probiotic organisms) proliferates to such a degree that the bad bacteria are unable to establish colonies in any significant number.
In other words, they out-compete the unhealthy bacteria and reduce negative effects associated with these organisms.
How to Use Acidophilus
Because of the need for adequate colonies in order for effects to be observable, it is necessary to take an effective dose of the probiotic selected.
Most health professionals will prescribe a specific dosage for the symptom or disease being treated and then recommend certain brands or methods of administration.
In people whose immune systems have been compromised, like those with HIV/AIDS or individuals who have had organ transplants and are on immunosuppressive medications, the good bacteria can overwhelm the system and become harmful.
For this reason, they should not take probiotics like Lactobacillus Acidophilus capsules unless carefully monitored by their doctor for any adverse side effects.
By the same token, it doesn’t do any good to take acidophilus supplements in amounts which are too minute to have the desired impact within the gut.
Many manufacturers are knowledgeable about the dosages and colony forming units (CFUs) required to create the intended effects.
Some food products boast they contain a significant quantity of acidophilus, but unless the bacteria has been handled properly all along the manufacturing, shipping and stocking process to assure the food product has not been exposed to certain temperature changes, light or oxygen, it is unlikely all the bacteria introduced at the time of production has remained alive. Acidophilus bacteria only work when they are alive.
Lactobacillus Acidophilus Side Effects?
Acidophilus side effects are rare and usually mild. For most healthy individuals, lactobacillus acidophilus works effectively to produce only beneficent results, without any negative effects whatsoever.
In some people, though, mild side effects like discomfort of the abdomen or flatulence (gas) occur though usually resolves with continued use.
People who are sensitive to lactose may be sensitive to acidophilus which is typically cultured on milk products and may have trace amounts of milk in it from the manufacturing process.
Though acidophilus is well tolerated in a majority of the general public, there are a few populations who should avoid taking acidophilus:
- Individuals whose immune system is known to be compromised
- Individuals with short bowel syndrome
- Individuals with allergies to milk
- Infants younger than six months
- Individuals with high fever
- Individuals with allergies to any of the filler materials such as gelatin or pectin
Drug Interactions
Acidophilus may affect insulin sensitivity, so should be used with care and monitored by a physician if taking drugs for diabetes orally.
In addition, in some people, acidophilus can interact with medications being taken which affect the immune system, arthritis, heart problems, some antibiotics, antivirals and some contraceptives.
Acidophilus may interact with some herbal supplements, as well. Be sure to tell your doctor about all medications you are taking before supplementing with acidophilus.
Is Acidophilus Safe to Take Every Day?
Acidophilus side effects are usually quite mild and typically subside over a short period of use. For abdominal discomfort, many doctors recommend cutting the dose and working up slowly to the maximum dose over a period of 1-2 weeks. This usually prevents recurrence of any symptoms.
Although almost everyone can supplement with acidophilus without any side effects, there are some rare cases where acidophilus side effects can become serious. As with all medications, follow your doctor’s instructions for best results.
- Lidbeck A, Nord CE, Gustafsson JA, Rafter J. Lactobacilli, anticarcinogenic activities and human intestinal microflora. Eur J Cancer Prev. 1992
- Dongarrà ML, Rizzello V, Muccio L, Fries W, Cascio A, Bonaccorsi I, Ferlazzo G. Mucosal immunology and probiotics. Curr Allergy Asthma Rep. 2013
- Neafsey PJ, Donat D. Bugs, drugs, and yogurt. Home Healthc Nurse. 2005
- Murina F, Graziottin A, Vicariotto F, De Seta F. Can Lactobacillus fermentum LF10 and Lactobacillus acidophilus LA02 in a slow-release vaginal product be useful for prevention of recurrent vulvovaginal candidiasis?: A clinical study. J Clin Gastroenterol. 2014
- Quigley EM. Probiotics in functional gastrointestinal disorders: what are the facts? Curr Opin Pharmacol. 2008
Article last updated on: April 27th, 2018 by Nootriment