What Is It?
Health Benefits
Dosage Information
Guidelines for Use
General Interaction
Possible Side Effects
Evidence Based Rating Scale

What Is It?

Many of us automatically think "bad" when we think "bacteria." After all, some bacteria can cause infections. But that notion may not always be true for your digestive tract, which contains a vast number of bacteria and has evolved to use "good" bacteria for several of its important functions.

Your digestive tract is host to about 400 different kinds of bacteria and yeasts. Among these, Lactobacillus acidophilus and other members of the Lactobacillus family are especially important to your health. Acidophilus is considered a "probiotic" bacteria because it helps to maintain intestinal health, and serves as a natural antibiotic against potentially harmful organisms. Taking acidophilus as a nutritional supplement will help maintain the normal balance of beneficial bacteria in the intestines and vagina.

Yet despite scientific evidence of the benefits of probiotics and their successful medicinal use elsewhere in the world, acceptance among conventional North American physicians has come slowly. A 2002 article in the journal Microbes and Infection, for instance, notes that our concern for "clean" has not only spawned multiple brands of antibacterial soaps and detergents, but may also explain a lack of widespread appreciation that bacteria can be good for health.

An excellent food source of acidophilus is yogurt, long valued for its therapeutic and nutritional benefits. However, there are wide variations in the quantities of acidophilus found in yogurt, and some brands contain none at all, making it difficult to get reliable amounts. To ensure quality, some commercial manufacturers add the active cultures after pasteurization, a heating process that can destroy both unwanted and beneficial organisms. Many brands will specify that their brands contain "live" or "active" cultures and list the specific names of the healthy bacteria found in their yogurt.

Acidophilus supplements are an effective alternative. These are sold in health-food stores, often in combination with Bifidobacteria, another group of organisms that function as probiotics. Many probiotic supplements are frequently combined with FOS (fructo-oligosaccharides), simple carbohydrates that stimulate the growth of healthy bacteria as they make their way through the digestive tract. FOS is actually a type of "prebiotic," indigestible food ingredients that stimulate the growth of probiotic bacteria already in the colon. Both probiotics and prebiotics can change the composition of intestinal bacteria in beneficial ways.

Health Benefits

Many people take acidophilus to treat and prevent digestive disorders, vaginal infections, and other illnesses. As it boosts benign and suppresses destructive bacteria, acidophilus allows the body to maintain a healthy bacterial balance. Acidophilus is often recommended as a safeguard during antibiotic therapy, which can suppress beneficial bacteria and trigger the growth of yeast infections.

Acidophilus may offer general health protection, as well. Several studies suggest that it functions as an immunity enhancer, and may suppress the toxic effects of carcinogens (cancer-causing agents).

Specifically, acidophilus is most commonly used to:

·  Ease irritable bowel syndrome. Acidophilus may bring relief to many people who suffer from irritable bowel syndrome (IBS), a constellation of gastrointestinal symptoms that include abdominal bloating, cramping, and diarrhea. A recent study in the American Journal of Gastroenterology found that acidophilus showed a significant benefit in 50% of patients with the primary symptoms of IBS (1). Other studies have replicated these effects (2-5).

·  Control traveler’s diarrhea and diarrhea resulting from antibiotic treatment. If your diarrhea is due to antibiotic use, acidophilus will help to correct the bacterial imbalances caused by the drug (6). Small trials have also demonstrated this protective effect in infants, showing up to 40% reductions in incidences of diarrhea (7). If you or your child are prone to antibiotic-associated diarrhea, it's probably a good idea to start both the acidophilus and medication at the same time. It may be wise to take acidophilus along on your next trip to the tropics, as well. Some strains of traveler's diarrhea may be weakened by acidophilus, perhaps because the immune-boosting effects of probiotics help to reduce intestinal inflammation (8).

·  Reduce flatulence. As it restores a healthy balance of bacteria in the digestive tract, acidophilus can keep gas-producers in the large intestine from multiplying. Increasing the gut's level of good bacteria relieves flatulence while lessening gas and bloating.

·  Combat vaginal yeast and other infections associated with Candida. A yeast that normally lives in harmony in your body, Candida albicans can begin to overgrow following antibiotic therapy. Chronic candidiasis such as this can produce digestive disturbances, fatigue, and allergies, among other symptoms. Because they promote a healthy intestinal environment, acidophilus and other probiotics can help to halt Candida overgrowthm (9). Using antibiotics only when truly necessary will also help you avoid the problem of Candida infection. A 2000 study in the International Journal of Gynecology and Obstetrics attributed the increase in recurring vaginal candidiasis worldwide to growing antibiotic resistance as well as to a lack of sufficient Lactobacilli in many women. According to the study's authors, Lactobacilli constitute "the vagina's primary defense mechanism against Candida (10)."

·  Relieve urinary tract infections. Lactobacilli such as acidophilus are the dominant members of healthy bacterial life in the urinary tract. Studies have shown that as "bacteriocins" or antibiotic-like substances, they are powerful enough to neutralize Escherichia (E.) coli bacteria, the source of many urinary tract infections (11).

·  Battle bad breath. As bacteria in your mouth work to break down food particles, they can multiply and release foul-smelling chemicals. Usually, good oral hygiene is adequate to clear out offensive mouth odors. But when you need extra help, adding acidophilus to your system can encourage more efficient digestion and reduce the number of odor-producing bacteria.

·  Relieve seasonal allergies. Animal studies have suggested that supplementation with acidophilus strains may protect against the stuffy nose and watery eyes that are the hallmarks of seasonal allergies. Preliminary human studies have reproduced this effect (12). More research will be necessary to determine if acidophilus will be added to the list of many herbal remedies used to treat seasonal allergies.

· Reduce high cholesterol. Research suggests that supplementation with the acidophilus found in probiotic milk or yogurt, may help reduce low density lipoprotein (LDL) or “bad” cholesterol thereby reducing the risk of heart disease (13, 14). These results while promising, have not been replicated in all studies (15, 16). More research is necessary before clinical recommendations can be made as to the utility of acidophilus in lowering cholesterol.

·  Prevent colds. In a year-long test, subjects who ate 3/4 cup of yogurt daily had 25% fewer colds than non-yogurt eaters. It's best to start at least three monthsahead of cold season, says researcher George Halpern of the University of California at Davis, because it takes time for yogurt to boost your resitance to germs. Halpern has found that that eating two cups of each day for four months spurred a fourfold increase in the body's production of gamma interferon, which helps fight infection. The protection lasted for two months after the yogurt-eating ended.

Note: Acidophilus has also been found to be useful for a number of other disorders. For information on these additional ailments, see our Dosage Recommendations Chart for Acidophilus.


  • tablet
  • suppository
  • powder
  • liquid
  • douche
  • capsule

Dosage Information

Special Tips:

--Look for probiotic supplements in the refrigerator section of your health foods store. Read the label to confirm that the product contains "live" or "active" cultures. Both heat and freezing temperatures will kill the acidophilus. Store acidophilus (regardless of its form) in the refrigerator or another dry, cool place. There are a few brands that are packaged to be effective if not refrigerated, but they tend to be more expensive. In general these forms are most convenient for frequent travelers.

--Check the expiration date. As there are numerous brands of probiotics, with a wide variety of strengths, forms, and concentrations, dosing should be guided by the instructions on the package or the advice of your health-care practitioner.

--Be aware that the amount of active cultures in acidophilus products can vary widely. Look for those that contain an effective quantity of organisms, between 1 and 2 billion per pill. In capsule forms, ideally there should be no fewer than 1 billion organisms per capsule.

-- Read labels carefully to confirm that the product contains live, or "active" cultures. Check the expiration date, too. Store acidophilus (regardless of its form) in the refrigerator or another dry, cool place. Both heat and freezing temperatures will kill live acidophilus.

--Acidophilus is often sold in preparations that combine acidophilus and another effective probiotic, Lactobacillus bifidus. Some may also include prebiotics such as FOS.

--Different strains work better in different parts of the body. Look for a supplement that has a variety of strains. Some manufacturers are even creating speciality blends emphasizing strains that contribute to intestinal health or urinary tract health. Typically, for an acute situation, probiotics are taken three times a day, whereas for a more chronic problem, or for prevention, reduce the dose to once or twice a day. As a general rule, probiotics are taken with food to reduce the number of organisms destroyed by stomach acid, or before bed so they have longer to sit in the intestine and do their good work.

  • For irritable bowel syndrome: On a maintenance basis, 2 pills a day, with at least 1 billion live organisms per pill; take with meals.
  • For urinary tract infections: Take 1 pill 4 times a day during the course of your antibiotic therapy.
  • For Candida overgrowth: Take capsules or powder with at least 1 billion live organisms twice a day for at least one month.
  • For vaginal yeast infections: Take 1 pill or capsule (with at least 1 billion live organisms per capsule) twice a day orally until the infection has cleared.
  • For diarrhea: Take 2 pills 3 times a day with meals.
  • For flatulence: Take 1 or 2 capsules of acidophilus or an acidophilus/bifidus combination between meals. Look for a dairy-free strain if you've determined that your gas may be due to lactose intolerance.
  • For bad breath: Take 2 pills twice a day between meals.
  • For antibiotic support: Take 2 pills three times a day with meals during the entire antibiotic course and one week afterward.


  • Guidelines for Use

  • If you are taking acidophilus during antibiotic therapy, take the acidophilus as many hours between the antibiotics as possible.


  • To make a vaginal douche, add 2 tsp. acidophilus powder to 1 quart warm water. Douche once a day. Do not use an acidophilus douche for more than 5 days as continuous use can actually cause an irritation of the vaginal walls.


  • When using powder forms, mix about one-half teaspoon with one-half cup of water, or follow package directions.


  • For liquid or suppository forms, follow the product's label directions.
  • ·  If you are attempting to treat chronic diarrhea recent study findings suggest that heat killed lactobacillus acidophilus was more effective than living lactobacillus cultures (17). Or a probiotic yeat product - Saccharomyces boulardii may be useful. Ask your doctor which kind of probiotic is right for your condition.


    General Interaction

    There are no known drug or nutrient interactions associated with acidophilus.

    Possible Side Effects

    Although acidophilus can ease flatulence, ironically, it may increase gassiness for a few days. This effect will ease as your intestines adjust to the bacterial shift.


  • See a doctor if you are experiencing the symptoms of a vaginal yeast infection for the first time. Many women believe they have a yeast infection when the culprit is actually a different bacteria, such as gardernella. Although using acidophilus will not worsen the situation, therapies directed at the specific bacteria are sometimes the most appropriate treatment.



    1. Nobaek S, Johansson M-L, Molin G, et al. Alteration of intestinal microflora is associated with reduction in abdominal bloating and pain in patients with irritable bowel syndrome. Am J Gastroenterol. 2000;95:1231–1238.
    2. Halpern GM, Prindiville T, Blankenberg M, et al. Treatment of irritable bowel syndrome with Lacteol Fort: a randomized, double-blind, cross-over trial. Am J Gastroenterol. 1996;91:1579–1585.
    3. Sen S, Mullan MM, Parker TJ, et al. Effect of Lactobacillus plantarum 299v on colonic fermentation and symptoms of irritable bowel syndrome. Dig Dis Sci. 2002;47:2615–2620.
    4. Saggioro A. Probiotics in the treatment of irritable bowel syndrome. J Clin Gastroenterol. 2004 Jul;38(6 Suppl):S104-6.
    5. Tsuchiya J, Barreto R, Okura R, Kawakita S, Fesce E, Marotta F. Single-blind follow-up study on the effectiveness of a symbiotic preparation in irritable bowel syndrome. Chin J Dig Dis. 2004;5(4):169-74.
    6. Madden JA, Plummer SF, Tang J, Garaiova I, Plummer NT, Herbison M, Hunter JO, Shimada T, Cheng L, Shirakawa T. Effect of probiotics on preventing disruption of the intestinal microflora following antibiotic therapy: a double-blind, placebo-controlled pilot study. Int Immunopharmacol. 2005 Jun;5(6):1091-7.
    7. Jirapinyo P, Densupsoontorn N, Thamonsiri N, Wongarn R. Prevention of antibiotic-associated diarrhea in infants by probiotics. J Med Assoc Thai. 2002 Aug;85 Suppl 2:S739-42.
    8. Scarpignato C, Rampal P. Prevention and treatment of traveler's diarrhea: a clinical pharmacological approach.Chemotherapy. 1995;41(suppl 1):48–81.
    9. Elmer GW, Surawicz CM, McFarland LV. Biotherapeutic agents. A neglected modality for the treatment and prevention of selected intestinal and vaginal infections. JAMA. 1996 Mar 20;275(11):870-6.
    10. Jeavons HS. Prevention and treatment of vulvovaginal candidiasis using exogenous Lactobacillus. J Obstet Gynecol Neonatal Nurs. 2003 May-Jun;32(3):287-96.
    11. Juarez Tomas MS, Ocana VS, Wiese B, Nader-Macias ME. Growth and lactic acid production by vaginal Lactobacillus acidophilus CRL 1259, and inhibition of uropathogenic Escherichia coli. J Med Microbiol. 2003 Dec;52(Pt 12):1117-24.
    12. Ishida Y, Nakamura F, Kanzato H, Sawada D, Hirata H, Nishimura A, Kajimoto O, Fujiwara S. Clinical effects of Lactobacillus acidophilus strain L-92 on perennial allergic rhinitis: a double-blind, placebo-controlled study. J Dairy Sci. 2005 Feb;88(2):527-33.
    13. Agerholm-Larsen L, Raben A, Haulrik N, Hansen AS, Manders M, Astrup A. Effect of 8 week intake of probiotic milk products on risk factors for cardiovascular diseases. Eur J Clin Nutr. 2000 Apr;54(4):288-97.
    14. Anderson JW,

    Date Published: 04/18/2005
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