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Dietary supplement

Stabilized Acidophilus Three Billion Ingredients & Drug Interactions

by NOW

Stabilized Acidophilus Three Billion label
See full label image
Tablet Or Pill Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Stabilized Acidophilus Three Billion against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Stabilized Acidophilus Three Billion is a dietary supplement by NOW with 1 active ingredient. Its ingredients are commonly taken for digestive health and balance, diarrhea (including antibiotic-related), vaginal yeast and bacterial infections.Based on those ingredients, 182 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Lactobacillus acidophilus. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Stabilized Acidophilus Three Billion by NOW

Ask about any prescription or over-the-counter medication and we check it for interactions with Stabilized Acidophilus Three Billion by NOW — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Stabilized Acidophilus Three Billion by NOW

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Sep 17, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: Lactobacillus acidophilus, a live probiotic bacterium at three billion colony-forming units per dose. It works by supporting the balance of beneficial bacteria in your digestive tract.

The tablet also contains inactive ingredients — maltodextrin, cellulose, silica, croscarmellose sodium, and stearic acid — which are fillers and binders that hold the tablet together.

Does it work?

Moderate evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: digestive health and balance.
  • We looked for evidence on: Antibiotic-associated diarrhea, Bacterial vaginosis, Clostridioides difficile infection, Colic, Constipation, Inflammatory bowel disease (IBD) — and 4 related terms.
  • The strongest evidence on file: Lactobacillus Acidophilus is rated "Possibly Effective" for Antibiotic-associated diarrhea (Natural Medicines).
  • Also on file: Lactobacillus Acidophilus is rated "Possibly Effective" for Bacterial vaginosis, Irritable bowel syndrome (IBS).
  • Also on file: Lactobacillus Acidophilus is rated "Insufficient Reliable Evidence To Rate" for Constipation, Inflammatory bowel disease (IBD), Lactose intolerance, Necrotizing enterocolitis (NEC).

The data we hold show that L. acidophilus is possibly effective for irritable bowel syndrome (IBS), antibiotic-associated diarrhea, Helicobacter pylori infection, and bacterial vaginosis. For atopic disease (allergic and inflammatory conditions), it's rated possibly ineffective.

For acute respiratory distress syndrome, the evidence isn't strong enough to rate it. If you're considering this for one of those uses, talk with your doctor about whether it fits your situation.

The evidence, ingredient by ingredient Lactobacillus Acidophilus

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Lactobacillus acidophilus is generally well tolerated in healthy adults and children. That said, because it's a live microorganism, there is a theoretical concern that it could cause infection in some patients — though such cases are rare and typically occur in people whose immune systems are already compromised or who have other serious health conditions.

Gastrointestinal side effects like bloating, gas, abdominal discomfort, or diarrhea can happen when taking L. acidophilus, especially in combination with other probiotics, but they're uncommon. Check with your doctor before starting, particularly if you have a weakened immune system or serious illness.

Side effects, ingredient by ingredient Lactobacillus Acidophilus

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Lactobacillus Acidophilus.
  • The most serious interaction on file is rated Moderate.
  • For scale: 182 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

If you're taking antibiotics, separate them from this probiotic by a few hours — taking them together may reduce the effectiveness of the L. acidophilus. Talk with your doctor or pharmacist about the best timing for your situation.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

This single-ingredient probiotic is a reasonable choice if you're interested in supporting gut health for IBS or antibiotic-associated diarrhea, though the evidence is promising rather than definitive. The main caution is timing: don't take it at the same time as antibiotics.

If you're on any medications or have a compromised immune system, confirm with your doctor or pharmacist that it's right for you.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Dec 24, 2013.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Stabilized Acidophilus Three Billion, straight from the product label.

Brand NOW
Barcode (UPC) 733739029133
Net contents 90 Tablet(s)
Market status On market
Date entered into DSLD Dec 24, 2013
DSLD ID 28589
Product type Non-nutrient/non-botanical
Supplement form Tablet Or Pill
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Stabilized Acidophilus Three Billion by NOW, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
UPC/BARCODE
733739029133
IngredientAmount% DV
Lactobacillus acidophilus3000000000 {Unit(s)}--

Other ingredients: Maltodextrin, Cellulose, Silica, Croscarmellose Sodium, Stearic Acid

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

SUGGESTED USAGE: As a dietary supplement, take 1 tablet 1 to 3 times daily, preferably with or before meals. Consider taking these other NOW(R) products: Fiber-3(TM) and Optimal Digestive System.

FDA Disclaimer Statement

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Precautions

Caution: For adults only.

Not manufactured with wheat, gluten, soy, egg, fish, shellfish or tree nut ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.

Consult physician if pregnant/nursing, taking medication, or have a medical condition.

Keep out of reach of children.

Do Not Eat Freshness Packet. Keep in Bottle.

Contains milk.

Note for those highly sensitive to milk protein: This product may contain minute amounts of casein.

General Statements

For more product information visit www.nowfoods.com/2913

NOW is pleased to introduce Stabilized Acidophilus, a real-time lab-tested Acidophilus. Because some strains of Acidophilus are more stable than others, scientists have developed a proprietary method that optimizes growth medium during fermentation. This method uses specific fermentation and drying techniques to ensure that each batch of Stabilized Acidophilus contains the hardiest strains of this important probiotic. In addition, substantial overages are incorporated to guarantee full potency at room temperature for the entire life of the product. Finally, Stabilized Acidophilus is packaged in glass for maximum protection from moisture.*

Made in the USA

HEALTHY INTESTINAL FLORA - No Refrigeration Necessary - Promotes Positive Probiotic Balance - Supports Immune System*

This superior probiotic has been carefully formulated, handled and tested to ensure maximum stability and full labeled potency.

Please Recycle.

Formulation

Not manufactured with wheat, gluten, soy, egg, fish, shellfish or tree nut ingredients.

Formula

Contains milk.

Note for those highly sensitive to milk protein: This product may contain minute amounts of casein.

FDA Statement of Identity

A Dietary Supplement

Seals/Symbols

GMP QUALITY ASSURED

Storage

Store in a cool, dry place after opening.

General

CODE 2913B V4

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Stabilized Acidophilus Three Billion by NOW label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Stabilized Acidophilus Three Billion label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Stabilized Acidophilus Three Billion by NOW

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Tablet(s) Dosage formTablet Or Pill Amounts shown are per serving.

Lactobacillus acidophilus

Interacts with
182 drugs
3000000000 {Unit(s)} per serving

Lactobacillus acidophilus is a 'friendly' bacterium used as a probiotic to support gut and vaginal health. It is generally well tolerated in healthy p...

Lactobacillus acidophilus monograph & interactions

Other (inactive) ingredients: Maltodextrin, Cellulose, Silica, Croscarmellose Sodium, Stearic Acid. These complete the product’s ingredient list but are not active constituents.

Interaction report

Stabilized Acidophilus Three Billion by NOW Drug Interactions

Want to check YOUR meds against Stabilized Acidophilus Three Billion?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
182Drugs
182 Moderate

Ingredients driving the most interactions

Lactobacillus acidophilus 182

Individual Drug Interactions

The ingredients in Stabilized Acidophilus Three Billion interact with 182 drugs. Click any drug to see the details.

1 of the 1 ingredient in Stabilized Acidophilus Three Billion interact with drugs. Each result below shows which ingredient is responsible. Lactobacillus acidophilus

Each ingredient & the kinds of drugs it affects

For each ingredient in Stabilized Acidophilus Three Billion with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Lactobacillus acidophilus1 drug type · 182 drugs

Antibiotic Drugs

Theoretically, taking Lactobacillus acidophilus with antibiotic drugs might decrease the effectiveness of L. acidophilus.
L. acidophilus preparations usually contain live and active organisms. Therefore, simultaneously taking antibiotics might kill a significant number of the organisms. Tell patients to separate administration of antibiotics and L. acidophilus preparations by at least two hours.

Likelihood Probable Evidence D
Lactobacillus acidophilus full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Stabilized Acidophilus Three Billion, from the product label.

NOW

See all NOW products
Web Address
www.nowfoods.com
Pharmacist Counseling Corner

Stabilized Acidophilus Three Billion by NOW: Common Questions

Does Stabilized Acidophilus Three Billion by NOW interact with any medications?
Yes. Based on its ingredients, Stabilized Acidophilus Three Billion has a known interaction with 182 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Stabilized Acidophilus Three Billion contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this while I'm on an antibiotic?
Yes, but not at the same time. Antibiotics can kill off the live bacteria in this probiotic, making it less effective. Space them a few hours apart — your doctor or pharmacist can help you figure out the best schedule.
Will this help my irritable bowel syndrome?
L. acidophilus is possibly effective for IBS, meaning the evidence suggests it may help, but it's not a guarantee. Talk with your doctor about whether it's worth trying as part of your IBS management.
Can I take this if I'm pregnant or breastfeeding?
In pregnancy, L. acidophilus is rated possibly safe — meaning the data suggest it's probably okay, but there isn't a lot of research. There's no rating on file for breastfeeding. Ask your doctor or pharmacist for personalized advice before starting.
What side effects should I watch for?
Most people tolerate it well. Some may notice gas, bloating, abdominal discomfort, or diarrhea, especially if they're also taking other probiotics — but these are uncommon. If they're severe or don't settle, check in with your doctor.
Is this safe if my immune system is compromised?
Since this contains live organisms, it's not automatically a safe choice for people with weakened immunity. Talk with your doctor first — they know your situation and can advise whether this probiotic is right for you.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Stabilized Acidophilus Three Billion label
Go deeper

The Full Monographs Behind Stabilized Acidophilus Three Billion’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Lactobacillus Acidophilus

Interacts with 182 drugs

Lactobacillus acidophilus is a 'friendly' bacterium used as a probiotic to support gut and vaginal health. It is generally well tolerated in healthy people, and there is reasonable evidence...

Read the full Lactobacillus Acidophilus monograph →
Sources

Sources & How We Checked

Stabilized Acidophilus Three Billion's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 15 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Lactobacillus Acidophilus 15 references
  1. Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.
  2. Begtrup LM, de Muckadell OB, Kjeldsen J, Christensen RD, Jarbøl DE. Long-term treatment with probiotics in primary care patients with irritable bowel syndrome--a randomised, double-blind, placebo controlled trial. Scand J Gastroenterol 2013;48(10):1127-35 PubMed
  3. Chatterjee S, Kar P, Das T, Ray S, Gangulyt S, Rajendiran C, Mitra M. Randomised placebo-controlled double blind multicentric trial on efficacy and safety of Lactobacillus acidophilus LA-5 and Bifidobacterium BB-12 for prevention of antibiotic-associated
  4. Shavakhi A, Tabesh E, Yaghoutkar A, Hashemi H, Tabesh F, Khodadoostan M,Minakari M, Shavakhi S, Gholamrezaei A. The effects of multistrain probiotic compound on bismuth-containing quadruple therapy for Helicobacter pylori infection: a randomized placebo-c
  5. Karamali M, Dadkhah F, Sadrkhanlou M, et al. Effects of probiotic supplementation on glycaemic control and lipid profiles in gestational diabetes: a randomized, double-blind, placebo-controlled trial. Diabetes Metab 2016;42(4):234-41. PubMed
  6. Badehnoosh B, Karamali M, Zarrati M, et al. The effects of probiotic supplementation on biomarkers of inflammation, oxidative stress and pregnancy outcomes in gestational diabetes. J Matern Fetal Neonatal Med. 2018 May;31(9):1128-1136.
  7. Kumar S, Kumar R, Rohilla L, Jacob N, Yadav J, Sachdeva N. A high potency multi-strain probiotic improves glycemic control in children with new-onset type 1 diabetes mellitus: A randomized, double-blind, and placebo-controlled pilot study. Pediatr Diabete
  8. Shahriari A, Karimi E, Shahriari M, Aslani N, Khooshideh M, Arab A. The effect of probiotic supplementation on the risk of gestational diabetes mellitus among high-risk pregnant women: A parallel double-blind, randomized, placebo-controlled clinical trial PubMed
  9. Xiao SD, Zhang DZ, Lu H, et al. Multicenter, randomized, controlled trial of heat-killed Lactobacillus acidophilus LB in patients with chronic diarrhea. Adv Ther. 2003;20(5):253-60.
  10. Rossi F, Amadoro C, Gasperi M, Colavita G. Lactobacilli infection case reports in the last three years and safety implications. Nutrients. 2022;14(6):1178. PubMed
  11. Ozer M, Goksu SY, Shahverdiani A, Mustafa M. Lactobacillus acidophilus-induced endocarditis and associated splenic abscess. Case Rep Infect Dis 2020;2020:1382709.
  12. Sadrin S, Sennoune S, Gout B, et al. A 2-strain mixture of Lactobacillus acidophilus in the treatment of irritable bowel syndrome: A placebo-controlled randomized clinical trial. Dig Liver Dis 2020;52(5):534-540. PubMed
  13. Stoffer JN, Slingsby TJ, Giuliari GP. Lactobacillus acidophilus endophthalmitis after intravitreal bevacizumab injection requiring intraocular lens explantation. Can J Ophthalmol 2022;57(1):e21-e22. PubMed
  14. Cukovic-Cavka S, Likic R, Francetic I, Rustemovic N, Opacic M, Vucelic B. Lactobacillus acidophilus as a cause of liver abscess in a NOD2/CARD15-positive patient with Crohn's disease. Digestion 2006;73(2-3):107-10.
  15. Hui J, Ren Y, Wang Y, Han Q. Lactobacillus acidophilus endophthalmitis postcataract operation: A case report with a literature review. Ocul Immunol Inflamm 2023.

See these in context on the Lactobacillus Acidophilus monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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