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Dietary supplement

Acidophilus Two Billion Ingredients & Drug Interactions

by NOW

Acidophilus Two Billion label
See full label image
Powder Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 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. 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 12, 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 powder contains one active ingredient: Lactobacillus acidophilus, a beneficial live bacteria that naturally lives in your gut. It's meant to support digestive and immune health.

The powder also has maltodextrin as an inactive ingredient to keep it stable.

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: maintain healthy intestinal flora.
  • 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 evidence supports L. acidophilus for several digestive concerns. It's possibly effective for irritable bowel syndrome (IBS), antibiotic-associated diarrhea, and bacterial vaginosis.

It's also possibly effective against Helicobacter pylori, a bacterium linked to stomach ulcers. For atopic disease (eczema and allergies), the evidence suggests it's possibly ineffective.

The data on its use for acute respiratory distress syndrome isn't reliable enough to rate yet.

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.

L. acidophilus is generally well tolerated in healthy adults and children. Gastrointestinal side effects — like belly discomfort, gas, bloating, or diarrhea — can happen but are uncommon, especially when combined with other probiotics.

There's a theoretical concern that live bacteria could cause infection in certain patients (bacteremia, sepsis, or other serious conditions), but this is rare and usually happens only in people whose immune system is very weak or who already have these bacteria present elsewhere in their body. Because data are limited, check with your doctor before use.

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 (Moderate interaction). Timing them apart from this probiotic will help both work better.

Check your exact antibiotic with the medication search tool on this page before you start, and ask your pharmacist how many hours to wait between doses.

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.

Acidophilus Two Billion may help with IBS, antibiotic-related diarrhea, or bacterial vaginosis if the evidence applies to you. If you take antibiotics, separate them from this probiotic by several hours — the timing matters.

Talk to your pharmacist about the exact schedule and whether this product is right for your situation.

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 Oct 1, 2012.

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) 733739029164
Net contents 4 oz.; 113 g
Market status On market
Date entered into DSLD Oct 1, 2012
DSLD ID 13943
Product type Non-nutrient/non-botanical
Supplement form Powder
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 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:
0.5 tsp
Maximum serving Sizes:
0.5 tsp
Servings per container
113
UPC/BARCODE
733739029164
IngredientAmount% DV
Lactobacillus acidophilus2000000000 CFU--

Other ingredients: Maltodextrin

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 1/2 teaspoon 1 to 2 times daily between meals or on an empty stomach. Consider taking these other NOW(R) products: Fiber-3(TM) and Optimal Digestive System.

Storage

KEEP REFRIGERATED TO MAINTAIN POTENCY.

General Statements

This NOW product has been designed to provide the most prominent type of resident bacteria in the small intestine. Regular intake of beneficial probiotics can aid in maintaining healthy intestinal flora.*

HEALTHY INTESTINAL FLORA

• Promotes Positive Probiotic Balance • Supports Immune System*

This product is sold by weight not volume. Please Recycle.

For more product information visit www.nowfoods.com/2916

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.

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

Keep out of reach of children.

Do not Eat freshness packet Enclosed.

Produced in a GMP facility that process other ingredients containing these allergens.

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

General

CODE 2916 V3

FDA Statement of Identity

A Dietary Supplement

Seals/Symbols

GMP QUALITY ASSURED

Formula

Contains milk.

Formulation

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

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 size0.5 tsp Dosage formPowder Servings per container113 Amounts shown are per serving.

Lactobacillus acidophilus

Interacts with
182 drugs
2000000000 CFU 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. 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 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

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 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 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
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.
Will this probiotic work if I'm on an antibiotic?
Not well if you take them at the same time — antibiotics kill the live bacteria in this product. The solution is simple: take them several hours apart so the antibiotic doesn't destroy the probiotic. Your pharmacist can tell you the exact timing for your antibiotic.
What digestive issues can L. acidophilus actually help with?
The evidence is strongest for IBS, antibiotic-related diarrhea, and bacterial vaginosis — in those cases it's possibly effective. It may also help against H. pylori bacteria. For other conditions, the data either suggest it won't help (atopic disease) or there isn't enough evidence yet (like severe lung disease).
Are there common side effects?
Most people tolerate it well. Some experience mild gas, bloating, belly discomfort, or loose stool — but these are uncommon. If you notice severe or persistent symptoms, mention it to your doctor.
Is it safe to take during pregnancy?
The data suggest it's possibly safe in pregnancy, but because the evidence is limited, talk with your doctor or midwife before you start. They know your full health picture and can give you personalized advice.
What is maltodextrin in this powder?
It's an inactive ingredient — a starch used to keep the powder stable and make it easier to measure. It's not a therapeutic part of the product.
Can I take this with other probiotics?
The data mention that combining L. acidophilus with other probiotics may cause gastrointestinal side effects like gas or belly pain, though these are uncommon. If you're thinking of combining them, ask your pharmacist first.

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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