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Ingredient file // Other

Montmorillonite Clay

A processing clay with oversold health claims

Montmorillonite is an absorbent mineral mined and milled for use in animal feed. It helps dry mixtures flow and serves as a binder. Dog studies involving related clays do not show that the amount in ordinary food treats diarrhea or detoxifies dogs.

Role in the food Does a job
What it is
A mined, absorbent clay mineral used in feed mixtures as an anticaking agent and binder.
Made from
Mined clay deposits
Main job
Feed processing aid
Typical amount
Not published
Watch for
Supplier screening for contaminants
Not the same as
Bentonite

Straight answer

Is Montmorillonite Clay safe for dogs?

Read it as a processing aid

When montmorillonite appears well down the ingredient list, judge the food by the ingredients above it and its nutritional adequacy statement. The clay has a plausible manufacturing job. Give little weight to promises that it detoxifies your dog, treats diarrhea or supplies useful minerals.

Why it is in the food
Feed processing aid

Our read // In our catalog

In 1 of every 21 foods we track

Share of foods that list it

5%

153 of the 3,204 foods with an ingredient list on file, from 7 brands. 86 dry dog food, 35 frozen dog food, 13 wet dog food.

Each square is 1% of the catalog

Where it sits on the label

Median position 11. In the top five of 4 foods, so it is usually a minor ingredient.

Top five List position, heaviest first

Above the salt

69%

Listed before the salt in 69% of foods. In the rest it is under about 1% of the recipe.

Price per lb

Foods with it $4.15
All foods $3.25

Median of the cheapest bag price across 74 priced foods, 28% above the catalog. The price is the food's, not the ingredient's.

Who leans on it

54%

of the foods that list it are from Instinct. 7 brands use it in total.

What it is

How it is made

Montmorillonite occurs in bentonite deposits mined for several industries, including animal feed. Suppliers crush, dry and grind the extracted clay so manufacturers can add it as a powder.6

  1. 01 // Source Clay deposit Bentonite deposits contain montmorillonite alongside other minerals, with the mix varying by source.
  2. 02 // Process Mined and crushed The clay is extracted from the ground and broken into smaller pieces.
  3. 03 // Process Dried and ground Suppliers remove moisture and mill the clay into a powder for feed manufacture.
  4. 04 // Output Clay powder The finished powder is packaged and shipped to manufacturers for blending into feed.

What is in it

Composition, dry matter

51.8-69.4

% silica

The range measured in one sodium montmorillonite deposit. It describes the clay's makeup, not a useful silicon dose for a dog.

Silicon dioxide 51.8-69.4%5
Aluminum oxide 9.3-15.7%5
Iron oxide 4.7-9.1%5
Calcium oxide 3.1-10.3%5

These dry matter ranges describe sodium clay from one deposit, not a pet food specification. Calcium clay from the same deposit had a different oxide mix, and other mined deposits vary too.5,6

Why it is in the bag

A processing aid that helps bind the food

  1. Main nutrition
  2. Supporting nutrient
  3. Does a job
  4. Mostly filler

Makers add montmorillonite for technical reasons. Clay swells when wet and helps feed particles hold together, and California feed rules allow bentonite, a clay rich in montmorillonite, as a pelleting aid at no more than 2% of the total ration. EFSA found an anticaking effect in premixes and complementary feeds, but no evidence it lasts in finished complete food. Where it usually sits on labels, it likely adds too little to change the food's nutrition.4,6,7

  1. 01

    Keeps premixes flowing

    Absorbent clay reduces caking while dry ingredients are blended. EFSA found an effect in premixes and complementary feeds, but could not show that it persists in complete feed.4

  2. 02

    Helps bind feed

    Clay swells when moistened and helps feed particles hold together. Feed rules recognize bentonite, which commonly contains montmorillonite, as a pelleting aid.6,7

  3. 03

    Uses a mined supply

    Mining and milling supply clay powder for animal feed. Bentonite is also mined for absorbents, drilling mud and industrial binding, giving suppliers uses beyond pet food.6,9

How much A dog challenge tested 0.5% of a related clay; a typical amount of montmorillonite in dog food is not published.2

Our read // The claims

What the evidence supports

Strong: controlled studies in dogs agree. Some: small or mixed dog data. Thin: mechanism or lab work only. None: nothing, or the evidence points the other way.

  1. Brands say

    Clay in food firms a dog's loose stool

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    In an open-label trial involving 60 dogs, medicinal smectite shortened chemotherapy diarrhea to a median of 19.5 hours versus 53 hours. A separate trial tested a paste with several ingredients. Neither measured montmorillonite at its usual food dose.1,3

  2. Brands say

    Clay binds aflatoxin before a dog absorbs it

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    In a 6-dog crossover challenge, food coated with 0.5% of a related aluminosilicate clay reduced a urinary aflatoxin marker by 48.4%. That does not demonstrate the same effect for every montmorillonite source in ordinary food.2,6

  3. Brands say

    Prevents finished kibble from clumping

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    EFSA found anticaking effects in premixes at 20,000 mg/kg and complementary feeds at 10,000 mg/kg. It explicitly found no evidence that the effect persists at the lower concentrations reached in complete feed.4,10

  4. Brands say

    Removes bacteria and viruses from a dog

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    A brand says moistened clay grabs bacteria and viruses. In laboratory tests, some montmorillonite samples inhibited Staphylococcus aureus, while the tested samples did not inhibit E. coli. Those tests measured no virus removal or effect inside dogs.5,10

  5. Brands say

    Provides useful trace minerals for dogs

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    A brand promotes the clay's minerals. The measured dry clay is mostly mineral oxides, including 51.8 to 69.4% silicon dioxide in one deposit. Its composition does not show that dogs absorb a nutritionally useful amount from food.5,10

Straight answers

What owners ask

  1. Q01

    Is it just filler?

    No

    It has a processing role as a binder and anticaking aid. Its presence does not make a food more nutritious, and tests have not shown that it keeps finished kibble from clumping.4,7

  2. Q02

    Will it detox my dog?

    No proof

    A small dog challenge found less absorption of one fungal toxin with a related clay. It did not test everyday exposure, pathogens or broad detoxification. Judge those claims separately from the clay's processing use.2,10

  3. Q03

    Does it treat diarrhea?

    Not in food

    Medicinal smectite shortened chemotherapy diarrhea in one dog trial. Another trial used a paste containing montmorillonite, probiotics and fiber. Neither shows that the amount in ordinary dog food treats diarrhea.1,3

Who uses it

Brands, best sellers and the company it keeps

Top brands, by foods that list it

  1. Instinct 82 / 98
  2. Nature's Logic 32 / 32
  3. Wysong 11 / 20
  4. Open Farm 10 / 42
  5. Blue Seal 9 / 19
  6. Primal 8 / 8
  7. I and Love and You 1 / 23

Foods that list it / all the brand's recipes we track.

Usually listed with, share of the foods that list it

  1. Mixed Tocopherols 52%
  2. Chicken Fat 34%
  3. Carrots 33%
  4. Flaxseed 33%
  5. Chicken 33%
  6. Chicken Meal 28%
  7. Apples 27%
  8. Peas 26%
  9. Sweet Potatoes 25%
  10. Beef 24%
  11. Turkey Meal 22%
  12. Butternut Squash 21%

On the shelf

Foods that list Montmorillonite Clay

153 foods in our catalog list it. These 60 list it highest on the label.

Nature’s Logic Original Canine Can: Lamb Wet Dog FoodNature's LogicNature’s Logic Original Canine Can: Lamb Wet Dog FoodWet // No. 4 on the labelNature’s Logic Original Canine Can: Sardine Wet Dog FoodNature's LogicNature’s Logic Original Canine Can: Sardine Wet Dog FoodWet // No. 5 on the labelInstinct Original Grain-Free Wet Dog FoodInstinctInstinct Original Grain-Free Wet Dog FoodWet // No. 5 on the labelInstinct Original Food Real Beef Recipe Wet Dog FoodInstinctInstinct Original Food Real Beef Recipe Wet Dog FoodWet // No. 5 on the labelNature’s Logic Distinction Canine Sardine Recipe Dry Dog FoodNature's LogicNature’s Logic Distinction Canine Sardine Recipe Dry Dog FoodDry // No. 7 on the labelOpen Farm Pasture-raised Lamb Raw Freeze-Dried Dog FoodOpen FarmOpen Farm Pasture-raised Lamb Raw Freeze-Dried Dog FoodFreeze-Dried // No. 8 on the labelOpen Farm Farmer’s Table Pork Raw Freeze-Dried Dog FoodOpen FarmOpen Farm Farmer’s Table Pork Raw Freeze-Dried Dog FoodFreeze-Dried // No. 9 on the labelWysong Synorgon Dry Dog FoodWysongWysong Synorgon Dry Dog FoodDry // No. 9 on the labelNature’s Logic Distinction Canine Pork Recipe Dry Dog FoodNature's LogicNature’s Logic Distinction Canine Pork Recipe Dry Dog FoodDry // No. 9 on the labelPrimal Freeze-Dried Raw Scoopable Pronto Dog Food TopperPrimalPrimal Freeze-Dried Raw Scoopable Pronto Dog Food TopperTopper // No. 10 on the label
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Nature’s Logic Original Canine Can: Beef Wet Dog FoodNature's LogicNature’s Logic Original Canine Can: Beef Wet Dog FoodWet // No. 6 on the labelNature’s Logic Original Canine Can: Pork Wet Dog FoodNature's LogicNature’s Logic Original Canine Can: Pork Wet Dog FoodWet // No. 6 on the labelNature’s Logic Original Canine Can: Turkey Wet Dog FoodNature's LogicNature’s Logic Original Canine Can: Turkey Wet Dog FoodWet // No. 6 on the labelNature’s Logic Original Canine Can: Venison Wet Dog FoodNature's LogicNature’s Logic Original Canine Can: Venison Wet Dog FoodWet // No. 6 on the labelInstinct Original Food Real Chicken Recipe Grain-Free Wet Dog FoodInstinctInstinct Original Food Real Chicken Recipe Grain-Free Wet Dog FoodWet // No. 6 on the labelInstinct Limited Ingredient Diet Grain-Free Recipe with Real Turkey Dry Dog FoodInstinctInstinct Limited Ingredient Diet Grain-Free Recipe with Real Turkey Dry Dog FoodDry // No. 6 on the labelInstinct Limited Ingredient Diet Grain-Free Recipe with Real Salmon Dry Dog FoodInstinctInstinct Limited Ingredient Diet Grain-Free Recipe with Real Salmon Dry Dog FoodDry // No. 6 on the labelNature’s Logic Original Canine Chicken Feast Wet Dog FoodNature's LogicNature’s Logic Original Canine Chicken Feast Wet Dog FoodWet // No. 7 on the labelNature’s Logic Original Pure Naturals Sardine Recipe Dry Dog FoodNature's LogicNature’s Logic Original Pure Naturals Sardine Recipe Dry Dog FoodDry // No. 7 on the labelInstinct Limited Ingredient Diet Grain-Free Recipe with Real Lamb Dry Dog FoodInstinctInstinct Limited Ingredient Diet Grain-Free Recipe with Real Lamb Dry Dog FoodDry // No. 7 on the labelNature’s Logic Original Canine Can: Duck & Salmon Wet Dog FoodNature's LogicNature’s Logic Original Canine Can: Duck & Salmon Wet Dog FoodWet // No. 8 on the labelInstinct Original Food for Small Breed Dogs Real Beef Recipe Wet Dog FoodInstinctInstinct Original Food for Small Breed Dogs Real Beef Recipe Wet Dog FoodWet // No. 8 on the labelNature’s Logic Original Pure Naturals Beef Recipe Dry Dog FoodNature's LogicNature’s Logic Original Pure Naturals Beef Recipe Dry Dog FoodDry // No. 8 on the labelNature’s Logic Original Pure Naturals Chicken Recipe Dry Dog FoodNature's LogicNature’s Logic Original Pure Naturals Chicken Recipe Dry Dog FoodDry // No. 8 on the labelNature’s Logic Grain-Free Canine Beef Meal Feast Dry Dog FoodNature's LogicNature’s Logic Grain-Free Canine Beef Meal Feast Dry Dog FoodDry // No. 8 on the labelNature’s Logic Canine Turkey Meal Feast Dry Dog FoodNature's LogicNature’s Logic Canine Turkey Meal Feast Dry Dog FoodDry // No. 8 on the labelNature’s Logic Canine Sardine Meal Feast Dry Dog FoodNature's LogicNature’s Logic Canine Sardine Meal Feast Dry Dog FoodDry // No. 8 on the labelNature’s Logic Canine Pork Meal Feast Dry Dog FoodNature's LogicNature’s Logic Canine Pork Meal Feast Dry Dog FoodDry // No. 8 on the labelNature’s Logic Canine Lamb Meal Feast Dry Dog FoodNature's LogicNature’s Logic Canine Lamb Meal Feast Dry Dog FoodDry // No. 8 on the labelNature’s Logic Canine Chicken Meal Feast Dry Dog FoodNature's LogicNature’s Logic Canine Chicken Meal Feast Dry Dog FoodDry // No. 8 on the labelNature’s Logic Canine Beef Meal Feast Dry Dog FoodNature's LogicNature’s Logic Canine Beef Meal Feast Dry Dog FoodDry // No. 8 on the labelInstinct Original Food for Small Breed Dogs Real Chicken Recipe Grain-Free Wet Dog FoodInstinctInstinct Original Food for Small Breed Dogs Real Chicken Recipe Grain-Free Wet Dog FoodWet // No. 9 on the labelInstinct Raw Longevity Patties Cage-Free Chicken Recipe for Adults Ages 7+ Frozen Dog FoodInstinctInstinct Raw Longevity Patties Cage-Free Chicken Recipe for Adults Ages 7+ Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Longevity Patties Cage-Free Chicken Recipe Frozen Dog FoodInstinctInstinct Raw Longevity Patties Cage-Free Chicken Recipe Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Longevity Bites Cage-Free Chicken Recipe for Adults Ages 7+ Frozen Dog FoodInstinctInstinct Raw Longevity Bites Cage-Free Chicken Recipe for Adults Ages 7+ Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Longevity Bites Cage-Free Chicken Recipe Grain-Free Frozen Dog FoodInstinctInstinct Raw Longevity Bites Cage-Free Chicken Recipe Grain-Free Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Longevity Bites Grass-Fed Lamb Recipe Frozen Dog FoodInstinctInstinct Raw Longevity Bites Grass-Fed Lamb Recipe Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Signature Patties Real Chicken Recipe Frozen Dog FoodInstinctInstinct Raw Signature Patties Real Chicken Recipe Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Signature Bites Real Lamb Recipe Frozen Dog FoodInstinctInstinct Raw Signature Bites Real Lamb Recipe Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Signature Bites Real Chicken Recipe Frozen Dog FoodInstinctInstinct Raw Signature Bites Real Chicken Recipe Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Patties Cage-Free Chicken Recipe Frozen Dog FoodInstinctInstinct Raw Patties Cage-Free Chicken Recipe Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Bites Cage-Free Chicken Recipe for Seniors Frozen Dog FoodInstinctInstinct Raw Bites Cage-Free Chicken Recipe for Seniors Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Bites Grass-Fed Lamb Recipe Grain-Free Frozen Dog FoodInstinctInstinct Raw Bites Grass-Fed Lamb Recipe Grain-Free Frozen Dog FoodFrozen // No. 9 on the labelInstinct Raw Bites Cage-Free Chicken Recipe Frozen Dog FoodInstinctInstinct Raw Bites Cage-Free Chicken Recipe Frozen Dog FoodFrozen // No. 9 on the labelNature’s Logic Grain-Free Canine Duck & Salmon Meal Feast Dry Dog FoodNature's LogicNature’s Logic Grain-Free Canine Duck & Salmon Meal Feast Dry Dog FoodDry // No. 9 on the labelNature’s Logic Grain-Free Canine Chicken Meal Feast Dry Dog FoodNature's LogicNature’s Logic Grain-Free Canine Chicken Meal Feast Dry Dog FoodDry // No. 9 on the labelNature’s Logic Canine Venison Meal Feast Dry Dog FoodNature's LogicNature’s Logic Canine Venison Meal Feast Dry Dog FoodDry // No. 9 on the labelNature’s Logic Canine Rabbit Meal Feast Dry Dog FoodNature's LogicNature’s Logic Canine Rabbit Meal Feast Dry Dog FoodDry // No. 9 on the labelNature’s Logic Distinction Canine Chicken Recipe Dry Dog FoodNature's LogicNature’s Logic Distinction Canine Chicken Recipe Dry Dog FoodDry // No. 9 on the labelNature’s Logic Distinction Canine Beef Recipe Dry Dog FoodNature's LogicNature’s Logic Distinction Canine Beef Recipe Dry Dog FoodDry // No. 9 on the labelInstinct Raw Boost Grain-Free Recipe with Real Duck Dry Dog FoodInstinctInstinct Raw Boost Grain-Free Recipe with Real Duck Dry Dog FoodDry // No. 9 on the labelInstinct Limited Ingredient Diet Small Breed Grain-Free Recipe with Real Turkey Dry Dog FoodInstinctInstinct Limited Ingredient Diet Small Breed Grain-Free Recipe with Real Turkey Dry Dog FoodDry // No. 9 on the labelInstinct Original Grain-Free Recipe with Real Duck Dry Dog FoodInstinctInstinct Original Grain-Free Recipe with Real Duck Dry Dog FoodDry // No. 9 on the labelOpen Farm Surf & Turf Raw Freeze-Dried Dog FoodOpen FarmOpen Farm Surf & Turf Raw Freeze-Dried Dog FoodFreeze-Dried // No. 10 on the labelInstinct Raw Boost RawBoost+ Shakers Grass-Fed Beef Recipe Grain-Free Dog Food TopperInstinctInstinct Raw Boost RawBoost+ Shakers Grass-Fed Beef Recipe Grain-Free Dog Food TopperTopper // No. 10 on the labelInstinct Raw Boost RawBoost+ Mixers Multivitamin Recipe Dog Food TopperInstinctInstinct Raw Boost RawBoost+ Mixers Multivitamin Recipe Dog Food TopperTopper // No. 10 on the labelNature’s Logic Pure Naturals Grain-Free Chicken Recipe Dry Dog FoodNature's LogicNature’s Logic Pure Naturals Grain-Free Chicken Recipe Dry Dog FoodDry // No. 10 on the labelInstinct Raw Longevity Patties Cage-Free Chicken Recipe for Puppies Frozen Dog FoodInstinctInstinct Raw Longevity Patties Cage-Free Chicken Recipe for Puppies Frozen Dog FoodFrozen // No. 10 on the labelInstinct Raw Longevity Patties Farm-Raised Rabbit Recipe Frozen Dog FoodInstinctInstinct Raw Longevity Patties Farm-Raised Rabbit Recipe Frozen Dog FoodFrozen // No. 10 on the labelInstinct Raw Longevity Bites Cage-Free Chicken Recipe for Puppies Grain-Free Frozen Dog FoodInstinctInstinct Raw Longevity Bites Cage-Free Chicken Recipe for Puppies Grain-Free Frozen Dog FoodFrozen // No. 10 on the label

Sources

What we read

Checked September 1, 2026.

  1. 1 Chemotherapy-induced diarrhoea in dogs and its management with smectite: Results of a monocentric open-label randomized clinical trial Veterinary and Comparative Oncology, 2021 // Journal
  2. 2 Identification and reduction of urinary aflatoxin metabolites in dogs Food and Chemical Toxicology, 2004 // Journal
  3. 3 Efficacy of an orally administered anti-diarrheal probiotic paste (Pro-Kolin Advanced) in dogs with acute diarrhea: A randomized, placebo-controlled, double-blinded clinical study Journal of Veterinary Internal Medicine, 2019 // Journal
  4. 4 Safety and efficacy of montmorillonite-illite (FIMIX 1g557) for all animal species EFSA Journal, 2020 // Regulator
  5. 5 In vitro antimicrobial activity of layered silicate materials Russian Open Medical Journal, 2021 // Journal
  6. 6 Safety and efficacy of bentonite as a feed additive for all animal species EFSA Journal, 2017 // Regulator
  7. 7 Cal. Code Regs. Tit. 3, § 2805 - Technical Additives California Department of Food and Agriculture, n.d. // Regulator
  8. 8 Assessment of the feed additive consisting of bentonite (dioctahedral montmorillonite) as an anticaking agent for all animal species and as a substance for reduction of the contamination of feed by mycotoxins for pigs, poultry and ruminants for the renewal of its authorisation (BASF SE) EFSA Journal, 2026 // Regulator
  9. 9 Clays Statistics and Information U.S. Geological Survey, n.d. // Government
  10. 10 Ingredient Spotlight: Montmorillonite Clay Nature's Logic, n.d. // Industry
An ingredient on its own tells you very little. What matters is how much of it there is and where it sits in the list. That is why we weigh the top five rather than reacting to any single name further down. Back to the wiki

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