Drug & supplement interaction

Clay + Doxycycline

Doxycycline brand names: Vibra-Tabs, Vibramycin, Doryx, Monodox, Doxycin, and others.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Clay and Doxycycline in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Doxycycline states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Clay and Doxycycline

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Doxycycline and Clay in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Clay safety at a glance

Clay overall Use caution Topical use is generally low-risk, but oral clay can be contaminated with heavy metals.
Pregnancy Possibly Unsafe When used orally, long-term. Clay ingestion during pregnancy appears to be associated with an increased incidence of pre-eclampsia, hypertension, and/or edema.... Read the full pregnancy detail
Breastfeeding Avoid Not enough safety data; avoid taking clay by mouth while breastfeeding.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Doxycycline and Clay? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Doxycycline

Interactions in our licensed database are recorded against drug classes, not just single drug names. Doxycycline is filed under 9 classifications — including tetracycline antibiotics, antibiotic drugs, p-glycoprotein substrates. Clay has documented interactions with 2 drug classes — the most serious being cimetidine (tagamet) (moderate) and quinine (moderate) — and none of Doxycycline’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Clay Does Interact With Other Medications

Clay has 3 moderate known drug interactions in our database — Doxycycline isn’t one of them. If you take anything else, check it against the full list below.

Taking anything else?

Check Another of Your Medications Against Clay

Covers the 2,830 medications we’ve checked against Clay. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Clay and Doxycycline May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • Anemia Worth acting on Additional detail

    Clay

    “Orally, clay seems to be well tolerated when used short-term. Adverse effects are generally mild and include constipation, vomiting, and diarrhea. Long-term ingestion of clay has been associated with more serious adverse effects.”

    Clay · Natural Medicines adverse-effect record, reported in anemia.

    6 sources cited
    1. 26617. Wang JS, Luo H, Billam M, et al. Short-term safety evaluation of processed calcium montmorillonite clay (NovaSil) in humans. Food Addit Contam 2005;22(3):270-9. PubMed
    2. 98648. Kee BK, Morris JS, Slack RS, et al. A phase II, randomized, double blind trial of calcium aluminosilicate clay versus placebo for the prevention of diarrhea in patients with metastatic colorectal cancer treated with irinotecan. Support Care Cancer. 2015;2 PubMed
    3. 98652. Lin JX, Fan ZY, Lin Q, et al. A comparison of dioctahedral smectite and iodine glycerin cream with topical mouth rinse in treatment of chemotherapy induced oral mucositis: a pilot study. Eur J Oncol Nurs. 2015;19(2):136-41. PubMed
    4. 98646. Pérez-Gaxiola G, Cuello-García CA, Florez ID, Pérez-Pico VM. Smectite for acute infectious diarrhoea in children. Cochrane Database Syst Rev. 2018;4:CD011526. PubMed
    5. 98649. Mitchell NJ, Kumi J, Aleser M, et al. Short-term safety and efficacy of calcium montmorillonite clay (UPSN) in children. Am J Trop Med Hyg. 2014;91(4):777-85. PubMed
    6. 101813. Lai BY, Liang N, Cao HJ, et al. Pediatric Tui Na for acute diarrhea in children under 5 years old: A systematic review and meta-analysis of randomized clinical trials. Complement Ther Med. 2018;41:10-22. PubMed

    “Orally, habitual clay intake may lead to iron malabsorption and severe iron deficiency, and has been associated with anemia.”

    Clay · Natural Medicines adverse-effect record, reported in anemia.

    5 sources cited
    1. 26605. Mengel CE, Carter WA, Horton ES. Geophagia with iron deficiency and hypokalemia. Cachexia Africana. Arch Intern Med 1964;114:470-4. PubMed
    2. 26607. Minnich V, Okcuoglu A, Tarcon Y, et al. Pica in Turkey. II. Effect of clay upon iron absorption. Am J Clin Nutr 1968;21(1):78-86.
    3. 26611. Carpenter WM. Observations on Cachexia Africana, on habits and effects of dirt eating in negro race. New Orleans Med Surg J 1844;1:146-68.
    4. 26614. Blum M, Orton C, Rose L. The effect of starch ingestion on excessive iron association, abstracted. Ann Intern Med 1968;68:1165.
    5. 26622. Prasad AS, Halsted JA, Nadimi M. Syndrome of iron deficiency anemia, hepatospelenomegaly, hypogonadism, dwarfism and geophagia. Am J Med 1961;31:532-46.

    Doxycycline

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxycycline. Read the label on DailyMed ›

  • Reduced appetite / Diarrhea / Vomiting Additional detail

    Clay

    “Orally, the most commonly reported adverse effects in clinical trials is constipation. Vomiting and diarrhea have been reported rarely. Long-term ingestion of clay may induce constipation, diarrhea, heartburn, flatulence, loss of appetite, and vomiting after meals. Clay ingestion has also been associated with intestinal obstruction and necrotizing enteritis, leading to bowel perforation.”

    Clay · Natural Medicines adverse-effect record, reported in constipation.

    6 sources cited
    1. 98646. Pérez-Gaxiola G, Cuello-García CA, Florez ID, Pérez-Pico VM. Smectite for acute infectious diarrhoea in children. Cochrane Database Syst Rev. 2018;4:CD011526. PubMed
    2. 101813. Lai BY, Liang N, Cao HJ, et al. Pediatric Tui Na for acute diarrhea in children under 5 years old: A systematic review and meta-analysis of randomized clinical trials. Complement Ther Med. 2018;41:10-22. PubMed
    3. 98649. Mitchell NJ, Kumi J, Aleser M, et al. Short-term safety and efficacy of calcium montmorillonite clay (UPSN) in children. Am J Trop Med Hyg. 2014;91(4):777-85. PubMed
    4. 26611. Carpenter WM. Observations on Cachexia Africana, on habits and effects of dirt eating in negro race. New Orleans Med Surg J 1844;1:146-68.
    5. 26616. Andrews PL, Horn CC. Signals for nausea and emesis: Implications for models of upper gastrointestinal diseases. Auton Neurosci 2006;125(1-2):100-15. PubMed
    6. 26617. Wang JS, Luo H, Billam M, et al. Short-term safety evaluation of processed calcium montmorillonite clay (NovaSil) in humans. Food Addit Contam 2005;22(3):270-9. PubMed

    Doxycycline

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxycycline. Read the label on DailyMed ›

  • Swelling Additional detail

    Clay

    “Cases of hypokalemia-induced muscle weakness and muscle swelling have been reported after ingestion of large quantities of clay.”

    Clay · Natural Medicines adverse-effect record, reported in hypokalemia.

    3 sources cited
    1. 26606. Severance HW Jr, Holt T, Patrone NA, Chapman L. Profound muscle weakness and hypokalemia due to clay ingestion. South Med J 1988;81(2):272-4. PubMed
    2. 26615. Ukaonu C, Hill DA, Christensen F. Hypokalemic myopathy in pregnancy caused by clay ingestion. Obstet Gynecol 2003;102(5 Pt 2):1169-71. DOI
    3. 26627. Trivedi TH, Daga GL, Yeolekar ME. Geophagia leading to hypokalemic quadriparesis in a postpartum patient. J Assoc Physicians India 2005;53:205-7.

    Doxycycline

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxycycline. Read the label on DailyMed ›

Reported for Clay but not commonly for Doxycycline: a bowel blockage, a fast or pounding heartbeat, muscle weakness and severe muscle breakdown.

Effects for Doxycycline come from the ADVERSE REACTIONS section of its FDA label; effects for Clay come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Clay in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When used orally, long-term. Clay ingestion during pregnancy appears to be associated with an increased incidence of pre-eclampsia, hypertension, and/or edema. There is insufficient reliable information available about the safety of ingesting clay short-term during pregnancy.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

How to take them

Some Doxycycline Products Have a Food Rule — Clay Should Not Break It

At least one FDA label for a product containing Doxycycline says to take it on an empty stomach. Most supplements — Clay included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Doxycycline on its own and move Clay to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Doxycycline products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

2 DOSAGE AND ADMINISTRATION Take one Doxycycline capsule (40 mg) once daily in the morning on an empty stomach, preferably at least one hour prior to or two hours after meals.

From the Dosage and Administration section of the FDA label we read for Doxycycline — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Clay or Doxycycline

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Clay or Doxycycline, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Doxycycline

This page covers Clay only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Doxycycline page lists 166 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Oleander (major) and Siberian Cocklebur (major).

By severity: 7 major · 139 moderate · 20 minor.

From our pharmacist’s overview on the Doxycycline page

“St. John's wort is the supplement I would flag first for anyone on doxycycline (Vibramycin, Doryx), because it can speed the antibiotic out of the body and leave an infection undertreated.”

Reviewed by 2 · Jul 18, 2026

Open the Doxycycline interaction page

One more smart check

Taking Clay as Part of a Dietary Supplement Product? Check It for Interactions

We hold 17 real supplement products containing Clay, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Clay. Even though Clay itself has no known interaction with Doxycycline, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Clay and Doxycycline Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Clay
Steady interest

#889 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Doxycycline
Top 5%

#41 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Clay reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Clay and Doxycycline records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Clay

What is Clay?

  • Detox and digestive complaints
  • Skin care (masks, acne, irritation)
  • Diarrhea and upset stomach
  • Drawing out toxins or impurities
  • Wound and rash poultices

Clay is a fine, mineral-rich earth (such as bentonite or kaolin) used on the skin and sometimes taken by mouth for digestive and 'detox' purposes. Topical use for masks and minor skin issues is popular and generally low-risk, but swallowing clay carries real safety concerns, including possible contamination with lead and other heavy metals. Talk to a pharmacist or doctor before taking clay internally.

Mineral-rich clay (bentonite, kaolin, French green clay, and similar) · Powder, capsules, masks, poultices, suspensions/drinks

An interaction check asks whether these two react with each other — it does not ask whether Clay is a good idea for someone in your situation. Here is what our Clay record says about it on its own.

Clay: dosing

There is no well-established, standardized dose for clay, and no recommended safe amount for eating it. Because of contamination and absorption concerns, taking clay internally is generally not recommended without medical guidance.If you use a topical product, follow the label directions for how long to leave a mask on and how often to use it. Choose products that are independently tested for heavy metals.

From our Clay monograph — the full record covers uses, side effects and every documented interaction.

Read the full Clay monograph & all interactions
Medication

About Doxycycline

What Is Doxycycline Used For?

Brand names: Vibra-Tabs, Vibramycin, Doryx, Monodox, Doxycin, Doxy, Doxylin, Doxy-D, Periostat, Doxycycline Injection, Oracea, Xyrosa

Doxycycline belongs to the tetracycline family of antibiotics. It's prescribed for many types of bacterial infections, including respiratory tract infections, sexually transmitted infections (STIs), tick-borne illnesses like Rocky Mountain spotted fever, and eye infections. It's also used to help prevent malaria and, in some cases, as a helper treatment for severe acne.

In situations where penicillin-type antibiotics can't be used — due to allergy, for example — doxycycline can step in as an alternative. It should only be used for infections that are proven or strongly suspected to be caused by bacteria.

See full Doxycycline drug information
Keep checking

Other Drugs & Clay

Browse every other medication we’ve checked against Clay — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
3Moderate
0Minor
2,826No known interaction
Moderate

3 interactions

No interaction 2,826 drugs checked — show the list
Evidence & sources

Clay References

The 31 references that drive our Clay monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Gonzalez JJ, Owens W, Ungaro PC, et al. Clay ingestion: a rare cause of hypokalemia. Ann Intern Med 1982;97(1):65-6. PubMed
  2. Mengel CE, Carter WA, Horton ES. Geophagia with iron deficiency and hypokalemia. Cachexia Africana. Arch Intern Med 1964;114:470-4. PubMed
  3. Severance HW Jr, Holt T, Patrone NA, Chapman L. Profound muscle weakness and hypokalemia due to clay ingestion. South Med J 1988;81(2):272-4. PubMed
  4. Minnich V, Okcuoglu A, Tarcon Y, et al. Pica in Turkey. II. Effect of clay upon iron absorption. Am J Clin Nutr 1968;21(1):78-86.
  5. O'Rourke DE, Quinn JG, Nicholson JO, Gibson HH. Geophagia during pregnancy. Obstet Gynecol 1967;29(4):581-4.
  6. Edwards CE, McDonald S, Mitchell JK, et al. Effect of clay and cornstarch intake on women and their infants. J Amer Diet Assoc 1964;44:109-15. DOI
  7. Carpenter WM. Observations on Cachexia Africana, on habits and effects of dirt eating in negro race. New Orleans Med Surg J 1844;1:146-68.
  8. Ducrotte P, Dapoigny M, Bonaz B, Siproudhis L. Symptomatic efficacy of beidellitic montmorillonite in irritable bowel syndrome: a randomized, controlled trial. Aliment Pharmacol Ther 2005;21(4):435-44. PubMed
  9. Chang FY, Lu CL, Chen CY, Luo JC. Efficacy of dioctahedral smectite in treating patients of diarrhea-predominant irritable bowel syndrome. J Gastroenterol Hepatol 2007;22(12):2266-72. PubMed
  10. Blum M, Orton C, Rose L. The effect of starch ingestion on excessive iron association, abstracted. Ann Intern Med 1968;68:1165.
  11. Ukaonu C, Hill DA, Christensen F. Hypokalemic myopathy in pregnancy caused by clay ingestion. Obstet Gynecol 2003;102(5 Pt 2):1169-71. DOI
  12. Andrews PL, Horn CC. Signals for nausea and emesis: Implications for models of upper gastrointestinal diseases. Auton Neurosci 2006;125(1-2):100-15. PubMed
  13. Wang JS, Luo H, Billam M, et al. Short-term safety evaluation of processed calcium montmorillonite clay (NovaSil) in humans. Food Addit Contam 2005;22(3):270-9. PubMed
  14. Bateson EM, Lebroy T. Clay eating by Aboriginals of the Northern Territory. Med J Aust 1978;1 Suppl 1:1-3. PubMed
  15. Delaitre B, Lemaigre G, Acar JF, et al. [Necrotizing enteritis and geophagia]. Nouv Presse Med 1976;5(28):1743-6.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Clay and Doxycycline Together: Common Questions

Is it safe to take Clay with Doxycycline?
We do not list a known interaction between Clay and Doxycycline. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Clay and Doxycycline have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Clay and Doxycycline at the same time of day?
At least one FDA label for a product containing Doxycycline says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Doxycycline on its own and move Clay to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the Clay and Doxycycline combination checked?
Interactions in our licensed database are recorded against drug classes. Doxycycline is filed under 9 classifications, and Clay has documented interactions with 2 drug classes — none of Doxycycline's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Clay interact with any other medications?
Yes. Clay has 3 documented drug interactions in our database — Doxycycline is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Doxycycline interact with any supplements?
Yes. Doxycycline has documented interactions with 166 supplements in our database — Clay is not one of them. The Doxycycline interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Doxycycline and Clay?

Our pharmacists answer your medication & supplement questions — free.

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.