Interactions on record — worth a quick check against your medications. Based on 1 of 5 ingredients. Check your meds →
Dietary supplement

Theralac Ingredients & Drug Interactions

by Master Supplements

Theralac label
See full label image
Capsule 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 Theralac 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

Theralac is a dietary supplement by Master Supplements with 5 active ingredients. 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 Theralac by Master Supplements

Ask about any prescription or over-the-counter medication and we check it for interactions with Theralac by Master Supplements — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Theralac by Master Supplements

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

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 5 active ingredients.
  • “Proprietary Probiotic” is a proprietary blend — the label gives one combined amount (133.31 mg) without saying how much of each component you get.

Theralac contains five active probiotic ingredients: two strains of Bifidobacterium (animalis lactis Bi-07 and animalis lactis), two strains of Lactobacillus (acidophilus and rhamnosus), and one strain of Lactobacillus paracasei. These are live beneficial bacteria meant to support digestive and immune health.

The product also contains several inactive ingredients — microcrystalline cellulose, sodium alginate, hydroxypropyl methylcellulose, trisodium phosphate, magnesium stearate, silicon dioxide, calcium silicate, ascorbic acid, and LactoStim — which serve as fillers, binders, and stabilizers.

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 support and probiotic balance.
  • We looked for evidence on: Antibiotic-associated diarrhea, Bacterial vaginosis, Clostridioides difficile infection, Constipation, Irritable bowel syndrome (IBS), Lactose intolerance — 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, Radiation-induced diarrhea, Lactose intolerance, Rotaviral diarrhea.

Lactobacillus acidophilus, the one ingredient we can assess, is rated possibly effective for irritable bowel syndrome (IBS), Helicobacter pylori infection, antibiotic-associated diarrhea, and bacterial vaginosis. It's rated possibly ineffective for atopic disease, and the evidence is insufficient to rate it for acute respiratory distress syndrome (ARDS).

We don't hold effectiveness data for the other four 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, though the data are limited so check with your doctor before use. Some people may experience mild gastrointestinal side effects — abdominal pain, bloating, flatulence, diarrhea, or burping — but these are uncommon.

Because these are live bacteria, there's a theoretical concern they could cause infection in people with certain conditions, though this is rare; most documented cases have occurred in people with underlying health issues. We don't have pregnancy or breastfeeding safety information on file for any of these ingredients, so talk with your doctor or pharmacist if you're pregnant 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.

Antibiotic drugs are the main medication type to watch: taking them at the same time as Theralac may reduce how well the probiotic works. Separate the two by timing them apart.

We couldn't check the other four probiotic strains in this product for interactions, so if you take any medications, use the interaction checker on this page with your specific drugs.

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.

Theralac is a probiotic blend best considered if you're looking to support digestive health or manage conditions like IBS or antibiotic-associated diarrhea. If you're taking antibiotics, space out when you take this supplement — don't take them at the same time.

Check with your pharmacist or doctor before starting, especially if you have any underlying health conditions or take other medications.

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

Assessment coverage: 1 of 5 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Aug 22, 2025.

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 Theralac, straight from the product label.

Brand Master Supplements
Barcode (UPC) 804879057604
Net contents 30 Capsule(s)
Market status On market
Date entered into DSLD Aug 22, 2025
DSLD ID 336270
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), 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 Theralac by Master Supplements, 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 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
30
UPC/BARCODE
804879057604
IngredientAmount% DV
Bifidobacterium animalis lactis Bi-070 NP--
Proprietary Probiotic133.31 mg--
Lactobacillus acidophilus0 NP--
Bifidobacterium animalis lactis0 NP--
Lactobacillus rhamnosus0 NP--
Lactobacillus paracasei0 NP--

Other ingredients: Microcrystalline Cellulose, Sodium Alginate, Hydroxypropyl Methylcellulose, Trisodium Phosphate, Magnesium Stearate, Silicon Dioxide, Calcium Silicate, Ascorbic Acid, LactoStim

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 use: Take 1 capsule daily. Take 2 capsules a day for additional digestive support.

Precautions

Theralac can be taken with antibiotics; allow at least 3 hours separation.

Warning: If you are pregnant, nursing, on medication or have any medical condition consult a health care professional before using this product.

Discontinue use and consult a doctor if any adverse reaction occurs.

Keep out of reach of children.

Formulation

Theralac is a high potency probiotic supplement protected by 7 U.S. patents covering acid-proof delivery and prebiotic stimulation. Each batch is laboratory tested to meet strict quality control standards with results posted online.

100% Money Back Guarantee

Gluten free GMO free

Vegan

Supports regularity Broad spectrum probiotic Deep delivery

Contains No: Milk, Eggs, Gluten, Wheat, Soy, Casein, Nuts, Seafood, or Beef Products.

Storage

Guaranteed at the time of expiration when kept refrigerated.

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.

Formula

5 Probiotics 30 Billion CFU Patented Prebiotic

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

Theralac by Master Supplements label

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

Theralac 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 Theralac by Master Supplements

These are the 5 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Capsule(s) Dosage formCapsule Servings per container30 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Proprietary Probiotic

133.31 mg per serving
  • › Bifidobacterium animalis lactis Bi-07
  • › Lactobacillus acidophilus
  • › Bifidobacterium animalis lactis
  • › Lactobacillus rhamnosus
  • › Lactobacillus paracasei

Other (inactive) ingredients: Microcrystalline Cellulose, Sodium Alginate, Hydroxypropyl Methylcellulose, Trisodium Phosphate, Magnesium Stearate, Silicon Dioxide, Calcium Silicate, Ascorbic Acid, LactoStim. These complete the product’s ingredient list but are not active constituents.

Interaction report

Theralac by Master Supplements Drug Interactions

Want to check YOUR meds against Theralac?

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 Theralac interact with 182 drugs. Click any drug to see the details.

1 of the 5 ingredients in Theralac 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 Theralac 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 Theralac, from the product label.

Master Supplements

See all Master Supplements products
Name
Master Supplements, Inc.
City
Victoria
State
MN
ZipCode
55386
Phone Number
800 926-2961
Web Address
master-supplements.com
Pharmacist Counseling Corner

Theralac by Master Supplements: Common Questions

Does Theralac by Master Supplements interact with any medications?
Yes. Based on its ingredients, Theralac 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?
Theralac contains 5 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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.
If I'm on antibiotics, can I still take Theralac?
Yes, but timing matters. Antibiotics can kill off the live bacteria in Theralac, so separate when you take them — don't take them together. Ask your pharmacist for specific timing guidance based on your antibiotic.
What are these probiotic strains supposed to do?
Theralac contains live beneficial bacteria meant to support digestive and immune health. Lactobacillus acidophilus, the strain we have the most data on, is possibly effective for IBS, antibiotic-associated diarrhea, and a few other conditions.
Can Theralac cause side effects?
Most people tolerate it well, but some experience mild gastrointestinal symptoms like bloating, gas, or diarrhea — these are uncommon. In rare cases, people with certain health conditions have developed infections, though this is very unusual.
Is it safe to take Theralac while pregnant or breastfeeding?
We don't have pregnancy or breastfeeding safety information on file for these ingredients. Talk with your doctor or pharmacist for personalized advice based on your situation.
Does Theralac have a lot of fillers?
Theralac contains several inactive ingredients like cellulose, alginate, and magnesium stearate to make the capsule work and stay stable. These are standard in most supplements.

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

Not sure if Theralac 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.

Theralac label
Go deeper

The Full Monographs Behind Theralac’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

Theralac'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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