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Dietary supplement

Mega Acidophilus Ingredients & Drug Interactions

by Foster Regal

Mega Acidophilus 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 Mega Acidophilus 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

Mega Acidophilus is a dietary supplement by Foster Regal 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 Probiotic Blend. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Mega Acidophilus by Foster Regal

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

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HelloPharmacist Scorecard of Mega Acidophilus by Foster Regal

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 Aug 20, 2026

What’s inside

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 4 active ingredients.
  • “Probiotic Blend” is a proprietary blend — the label doesn't break down how much of each component you get.

Mega Acidophilus contains 4 active probiotic ingredients: Lactobacillus acidophilus, Lactobacillus salivarius, Lactobacillus bulgaricus, and Bifidobacterium animalis lactis. These are live beneficial bacteria meant to support gut health.

The product also contains inactive ingredients—calcium phosphate, gelatin, magnesium stearate, and calcium silicate—that help form and stabilize the capsule.

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 bacterial balance.
  • We looked for evidence on: Antibiotic-associated diarrhea, Bacterial vaginosis, Clostridioides difficile infection, Colic, Constipation, Helicobacter pylori — 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, Helicobacter pylori, Irritable bowel syndrome (IBS).
  • Also on file: Lactobacillus Acidophilus is rated "Insufficient Reliable Evidence To Rate" for Constipation, Inflammatory bowel disease (IBD), Lactose intolerance.

Lactobacillus acidophilus is possibly effective for irritable bowel syndrome (IBS), Helicobacter pylori infection, antibiotic-associated diarrhea, and bacterial vaginosis. The evidence suggests it may help with these conditions, though the data isn't conclusive.

For atopic disease (allergic and immune conditions), it's possibly ineffective, and for acute respiratory distress syndrome, we don't have enough reliable evidence to rate it. We hold no effectiveness information for the other three probiotic strains in this product.

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. Gastrointestinal side effects—stomach discomfort, abdominal pain, indigestion, gas, bloating, diarrhea, vomiting, or burping—can occur when taking it with other probiotics, but these events are uncommon.

In rare cases, the live bacteria have been detected in serious infections (bacteremia, sepsis, endocarditis, and others), though most of those cases appear to involve bacteria that moved from places where they occur naturally in the body. The data on safety for the other ingredients is limited.

There is not enough information to know whether this product is safe during pregnancy or breastfeeding—talk with your doctor or pharmacist before taking it if you are pregnant, planning pregnancy, or nursing.

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.

Separate Mega Acidophilus from antibiotic drugs by spacing doses apart, since antibiotics may kill the live organisms in the probiotic and reduce its effectiveness. Talk with your doctor or pharmacist about the right timing for your medications.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

This product may help with IBS, antibiotic-associated diarrhea, bacterial vaginosis, or H. pylori infection if you have one of those conditions. It's generally well tolerated, but because antibiotics can reduce its effectiveness, you'll want to time the two separately.

Before you start, check your medications with your doctor or pharmacist—especially if you take antibiotics—and confirm it's 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 4 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Feb 23, 2022.

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 Mega Acidophilus, straight from the product label.

Brand Foster Regal
Barcode (UPC) 364175942900
Net contents 90 Capsule(s)
Market status On market
Date entered into DSLD Feb 23, 2022
DSLD ID 260352
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar 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 Mega Acidophilus by Foster Regal, 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:
2 Capsule(s)
Maximum serving Sizes:
2 Capsule(s)
Servings per container
45
UPC/BARCODE
364175942900
IngredientAmount% DV
Lactobacillus acidophilus0 NP--
Lactobacillus salivarius0 NP--
Lactobacillus bulgaricus0 NP--
Bifidobacterium animalis lactis0 NP--
Probiotic Blend0 NP--

Other ingredients: Calcium Phosphate, Gelatin, Magnesium Stearate, Calcium Silicate

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

Directions: As a dietary supplement, take 2 capsules daily, preferably with a meal.

Precautions

Tamper evident: Do not use this product if imprinted foil seal under cap is broken or missing.

Keep out of reach of children.

Caution: If you are pregnant or nursing, consult your physician before taking this product.

Formulation

Mfg. in an FDA Registered Facility, using Good Manufacturing Practices (GMPs).

Conforms to USP <2091> for weight. Meets USP <2040> disintegration for maximum bioavailability.

Nutritionally supports healthy intestinal flora

Gluten free Contains: No artificial color, flavor or sweetener, no preservatives, no sugar, no starch, no milk, no lactose, no soy, no gluten, no wheat, no yeast, no fish, and is sodium free.

Made in USA

Storage

Keep tightly closed. Refrigerate after opening.

Formula

6 Billion good bacteria per 2 capsule serving at time of manufacture.

Probiotic freeze-dried Non-dairy with pectin

FDA Disclaimer Statement

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Brand IP Statement(s)

Foster Regal The best choice.

FDA Statement of Identity

Dietary Supplement

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

See for yourself

Mega Acidophilus by Foster Regal label

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

Mega Acidophilus 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 Mega Acidophilus by Foster Regal

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

Serving size2 Capsule(s) Dosage formCapsule Servings per container45 Amounts shown are per serving.

Probiotic Blend

Interacts with
182 drugs
0 NP 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...

Probiotic Blend monograph & interactions
  • › Lactobacillus acidophilus
  • › Lactobacillus salivarius
  • › Lactobacillus bulgaricus
  • › Bifidobacterium animalis lactis

Other (inactive) ingredients: Calcium Phosphate, Gelatin, Magnesium Stearate, Calcium Silicate. These complete the product’s ingredient list but are not active constituents.

Interaction report

Mega Acidophilus by Foster Regal Drug Interactions

Want to check YOUR meds against Mega Acidophilus?

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

Probiotic Blend 182

Individual Drug Interactions

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

1 of the 1 ingredient in Mega Acidophilus interact with drugs. Each result below shows which ingredient is responsible. Probiotic Blend

Each ingredient & the kinds of drugs it affects

For each ingredient in Mega Acidophilus 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.

Probiotic Blend1 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
Probiotic Blend full monograph & interactions
The maker

Brand information

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

Foster Regal

See all Foster Regal products
Name
Foster Regal Laboratories
Street Address
115 S.C.T. Ct.
City
White House
State
TN
ZipCode
37188
Pharmacist Counseling Corner

Mega Acidophilus by Foster Regal: Common Questions

Does Mega Acidophilus by Foster Regal interact with any medications?
Yes. Based on its ingredients, Mega Acidophilus 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?
Mega Acidophilus 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 with antibiotics?
Not at the same time. Taking them together might kill off the L. acidophilus in this product and make it less effective. Space your doses apart—ask your doctor or pharmacist exactly how many hours apart they should be.
What does L. acidophilus actually do?
It's a live beneficial bacterium that may help with IBS, antibiotic-associated diarrhea, bacterial vaginosis, and H. pylori infection. The evidence suggests it can help, but it's not proven for all situations.
Are there side effects?
Most people tolerate it well. Some experience mild stomach upset—bloating, gas, indigestion, or diarrhea—especially when combined with other probiotics, but these are uncommon. In very rare cases, the bacteria have caused serious infections in people who are severely ill or immunocompromised.
Can I take this while pregnant or breastfeeding?
We don't have enough data to know either way. Talk with your doctor or pharmacist before taking it if you're pregnant, planning to become pregnant, or nursing.
Why do I need to separate this from antibiotics?
This product contains live active organisms, and antibiotics kill bacteria—including the beneficial ones in the probiotic. Taking them at the same time means fewer live organisms survive to do their job.

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

Not sure if Mega Acidophilus is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.

Mega Acidophilus label
Go deeper

The Full Monographs Behind Mega Acidophilus’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

Mega Acidophilus'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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