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Dietary supplement

Acidophilus Two Billion Ingredients & Drug Interactions

by NOW

Acidophilus Two Billion label
See full label image
Capsule 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 Acidophilus Two 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

Acidophilus Two 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 LA-14. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Acidophilus Two Billion by NOW

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

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HelloPharmacist Scorecard of Acidophilus Two 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 Jul 11, 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 LA-14, a naturally occurring bacterium that lives in the human gut and is used as a probiotic supplement. The capsule also holds inactive ingredients—microcrystalline cellulose, hypromellose, stearic acid, and silicon dioxide—which are fillers and binders that hold the capsule 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: healthy intestinal flora and probiotic balance.
  • We looked for evidence on: Antibiotic-associated diarrhea, Bacterial vaginosis, Clostridioides difficile infection, Constipation, Inflammatory bowel disease (IBD), Irritable bowel syndrome (IBS) — 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), Radiation-induced diarrhea, Lactose intolerance.

The evidence for L. acidophilus is mixed. It's rated possibly effective for irritable bowel syndrome (IBS), H. pylori infection, antibiotic-associated diarrhea, and bacterial vaginosis.

For atopic disease (allergic and eczema-type conditions), it's rated possibly ineffective. For acute respiratory distress syndrome, there isn't enough reliable evidence yet to say whether it works.

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, the data are limited, so it's worth checking with your doctor before you start.

Since this product contains live microorganisms, there is a theoretical risk of infection in some patients—most reports involve people whose immune systems were already compromised or who had other serious medical conditions. Gastrointestinal side effects like bloating, gas, abdominal discomfort, or diarrhea are possible but uncommon when taken alone.

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.

Antibiotics are the main medication type to watch—they can reduce how well this probiotic works. Separate the timing of your antibiotic doses and this supplement by a few hours, and ask your pharmacist or doctor for the best schedule for your specific antibiotic.

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.

If you have IBS, antibiotic-related diarrhea, or bacterial vaginosis, this probiotic may be worth trying. If you're on antibiotics, time your doses apart so the medication doesn't kill off the live bacteria in the supplement.

Check with your doctor before starting, especially if you have a weak immune system or serious underlying illness.

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 May 23, 2024.

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 Acidophilus Two Billion, straight from the product label.

Brand NOW
Barcode (UPC) 733739029058
Net contents 100 Veg Capsule(s)
Market status On market
Date entered into DSLD May 23, 2024
DSLD ID 313550
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Kosher, Gluten Free, Dairy 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 Acidophilus Two 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 Veg Capsule(s)
Maximum serving Sizes:
1 Veg Capsule(s)
Servings per container
100
UPC/BARCODE
733739029058
IngredientAmount% DV
Lactobacillus acidophilus LA-1420 mg--

Other ingredients: Microcrystalline Cellulose, Hypromellose, Stearic Acid, Silicon Dioxide

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: Take 1 capsule 1 to 4 times daily between meals or on an empty stomach.

Storage

Keep refrigerated to maintain potency.

Settling of powder may occur in the capsule, which is filled by weight not volume.

Formula

Lactobacillus acidophilus, one of the most prominent types of resident bacteria in the intestinal tract, has been used as a probiotic for decades.

Triangle K (Kosher)

General Statements

It is well established that the gut is one of the most important components of the immune system and that the development and function of normal immune system function is influenced by the composition of the intestinal microflora. It has been shown that regular intake of probiotics can aid in maintaining a healthy intestinal flora.

Digestive Family owned since 1968.

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: Consult physician if pregnant/nursing, taking medication (especially immune-suppressing drugs), or have a medical condition (especially if immune system is compromised).

Keep out of reach of children.

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

Formulation

Healthy intestinal flora Promotes positive probiotic balance

Non-GMO Dairy, soy & gluten free

Vegetarian/Vegan

Made and quality tested in the USA with globally sourced ingredients. This product is formulated to deliver a potency of 2 billion CFU through the best by date.

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

Natural color variation may occur in this product.

The probiotic strain in this product has been identity-verified using DNA-fingerprinting technology.

FDA Statement of Identity

A Dietary Supplement

Seals/Symbols

Triangle K (Kosher) Strain Verified

GMP Quality Assured

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

See for yourself

Acidophilus Two Billion by NOW label

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

Acidophilus Two 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 Acidophilus Two Billion by NOW

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

Serving size1 Veg Capsule(s) Dosage formCapsule Servings per container100 Amounts shown are per serving.

Lactobacillus acidophilus LA-14

Interacts with
182 drugs
20 mg 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 LA-14 monograph & interactions

Other (inactive) ingredients: Microcrystalline Cellulose, Hypromellose, Stearic Acid, Silicon Dioxide. These complete the product’s ingredient list but are not active constituents.

Interaction report

Acidophilus Two Billion by NOW Drug Interactions

Want to check YOUR meds against Acidophilus Two 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 LA-14 182

Individual Drug Interactions

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

1 of the 1 ingredient in Acidophilus Two Billion interact with drugs. Each result below shows which ingredient is responsible. Lactobacillus acidophilus LA-14

Each ingredient & the kinds of drugs it affects

For each ingredient in Acidophilus Two 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 acidophilus LA-141 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 LA-14 full monograph & interactions
The maker

Brand information

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

NOW

See all NOW products
Name
NOW FOODS
Street Address
395 S. Glen Ellyn Rd.
City
Bloomingdale
State
IL
ZipCode
60108
Web Address
nowfoods.com
Pharmacist Counseling Corner

Acidophilus Two Billion by NOW: Common Questions

Does Acidophilus Two Billion by NOW interact with any medications?
Yes. Based on its ingredients, Acidophilus Two 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?
Acidophilus Two 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 Acidophilus Two Billion while I'm on an antibiotic?
You can take them together, but not at the same time. Antibiotics can kill off the live bacteria in this probiotic, making it less effective. Separate your doses by a few hours—your pharmacist can help you work out a schedule that gives the probiotic the best chance to survive.
What is Lactobacillus acidophilus, and what does it do?
It's a beneficial bacterium that naturally lives in your gut. This supplement is used to support digestive health and may help with conditions like irritable bowel syndrome, diarrhea caused by antibiotics, and certain infections, though the evidence is strongest for those first three.
Are there any side effects I should know about?
Most people tolerate it well. Uncommon side effects include bloating, gas, stomach discomfort, or loose stool. In rare cases, live probiotic bacteria can cause serious infection, but this is almost always in people with weakened immune systems.
Is this safe for children?
Lactobacillus acidophilus is generally well tolerated in children, but check with your child's doctor before starting it, since the data are limited for pediatric use.
Can I take this if I'm pregnant or breastfeeding?
We don't have safety data on file for Lactobacillus acidophilus in pregnancy or breastfeeding. Talk with your doctor or midwife before taking it so you can make a decision based on your individual situation.

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

Not sure if Acidophilus Two Billion is safe with your meds?

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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.

Acidophilus Two Billion label
Go deeper

The Full Monographs Behind Acidophilus Two 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

Acidophilus Two 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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