Drug & supplement interaction

Kefir + Regorafenib

Regorafenib brand name: Stivarga.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Kefir and Regorafenib 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 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

Kefir and Regorafenib

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 Regorafenib and Kefir 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.

Kefir safety at a glance

Kefir overall Generally safe Kefir is generally safe for most healthy people as a food.
Pregnancy Use caution Pasteurized-milk kefir is likely fine, but avoid unpasteurized or homemade versions and consult your doctor.
Breastfeeding Use caution Likely fine as a food, but choose pasteurized products and check with your doctor.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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

Why No Interaction Is Listed for Regorafenib

Interactions in our licensed database are recorded against drug classes, not just single drug names. Regorafenib is filed under 2 classifications — cytochrome p450 3a4 (cyp3a4) substrates, oral drugs. Kefir has documented interactions with 2 drug classes — the most serious being immunosuppressants (moderate) and disulfiram (antabuse) (minor) — and none of Regorafenib’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

Kefir Does Interact With Other Medications

Kefir has 121 moderate, 1 minor known drug interactions in our database — Regorafenib isn’t one of them. If you take anything else, check it against the full list below.

Moderate 121 Minor 1 No known interaction 2,708 (incl. Regorafenib)
Taking anything else?

Check Another of Your Medications Against Kefir

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

What to actually watch for

No Interaction Found — But Data Suggests Kefir and Regorafenib 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.

  • Diarrhea / Stomach pain / Nausea reported in 12.3% of FDA reports for Regorafenib Additional detail

    Kefir

    “Orally, kefir might cause bloating, nausea, intestinal cramping, diarrhea, and constipation with initial use. These symptoms are uncommon and usually resolve after continued use. However, severe bloating and abdominal cramping resulting in withdrawal from a clinical trial has been reported for 3 patients.”

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

    4 sources cited
    1. 7636. St-Onge MP, Farnworth ER, Savard T, et al. Kefir consumption does not alter plasma lipid levels or cholesterol fractional synthesis rates relative to milk in hyperlipidemic men: a randomized controlled trial [ISRCTN10820810]. BMC Complement Altern Med 200 PubMed
    2. 95314. Turan I, Dedeli Ö, Bor S, Ilter T. Effects of a kefir supplement on symptoms, colonic transit, and bowel satisfaction score in patients with chronic constipation: a pilot study. Turk J Gastroenterol. 2014;25(6):650-6. PubMed
    3. 112046. Bellikci-Koyu E, Sarer-Yurekli BP, Karagozlu C, Aydin-Kose F, Ozgen AG, Buyuktuncer Z. Probiotic kefir consumption improves serum apolipoprotein A1 levels in metabolic syndrome patients: a randomized controlled clinical trial. Nutr Res 2022;102:59-70. PubMed
    4. 95311. Fathi Y, Faghih S, Zibaeenezhad MJ, Tabatabaei SH. Kefir drink leads to a similar weight loss, compared with milk, in a dairy-rich non-energy-restricted diet in overweight or obese premenopausal women: a randomized controlled trial. Eur J Nutr. 2016;55(1) PubMed

    Regorafenib

    Listed in the ADVERSE REACTIONS section of the FDA label for Regorafenib, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Kefir but not commonly for Regorafenib: constipation and bloating or gas.

Effects for Regorafenib come from the ADVERSE REACTIONS section of its FDA label; effects for Kefir come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 11,442 voluntary FDA FAERS reports for Regorafenib that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Everything else you take

See Every Supplement That Interacts With Regorafenib

This page covers Kefir only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Regorafenib page lists 138 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 94 moderate · 41 minor.

From our pharmacist’s overview on the Regorafenib page

“Regorafenib (Stivarga) is a targeted oral cancer therapy, and with a drug like this the goal is keeping its blood level inside a fairly tight window, so the 138 supplements and herbs on this page deserve real respect. Nearly all of them, 121 in total, can shift how the liver enzyme CYP3A4 processes the drug, nudging its level up or down.”

Reviewed by 2 · Jul 18, 2026

Open the Regorafenib interaction page

One more smart check

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

We hold 29 real supplement products containing Kefir, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Kefir. Even though Kefir itself has no known interaction with Regorafenib, 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 Kefir and Regorafenib 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 Kefir
Steady interest

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

29 days ago today
Medication Regorafenib
Top half

#1,313 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 Kefir reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Kefir and Regorafenib records this page draws on were last updated July 10, 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 Kefir

What is Kefir?

  • Digestive health
  • Source of probiotics
  • Lactose intolerance support
  • General immune support
  • Gut microbiome balance

Kefir is a fermented drink made by adding kefir grains to milk (or sugar water), creating a tangy beverage rich in probiotics. It is generally a safe, nutritious food that may support gut health, but strong evidence for treating specific medical conditions is still limited. If you have a weakened immune system or other health concerns, check with your pharmacist or doctor first.

Fermented milk or water with kefir grains (a culture of bacteria and yeast) · Drinkable fermented milk, water kefir, powdered or capsule probiotic products

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

Kefir: dosing

There is no official standardized dose for kefir because it is a food, not a regulated medicine. Many people drink anywhere from a few ounces to a cup per day, often starting small and increasing gradually to allow the gut to adjust.If you use a powdered or capsule probiotic product, follow the directions on the label.

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

Read the full Kefir monograph & all interactions
Medication

About Regorafenib

What Is Regorafenib Used For?

Brand name: Stivarga

Stivarga is approved to treat three types of advanced cancer in adults. It is used for metastatic colorectal cancer (cancer that has spread) after prior chemotherapy and targeted therapy; for locally advanced, unresectable, or metastatic gastrointestinal stromal tumor (GIST) after two previous treatments; and for hepatocellular carcinoma (liver cancer) after treatment with sorafenib.

All three uses are specific to Stivarga tablets taken by mouth. It is intended for patients whose cancer has progressed despite earlier lines of therapy.

Most-Reported Side Effects for Regorafenib

From FAERS, the FDA’s public side-effect reporting system (11,542 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 1,769 reports
Palmar-plantar erythrodysaesthesia syndrome 1,439 reports
Diarrhea 1,418 reports
Decreased appetite 1,091 reports
Asthenia 946 reports
See full Regorafenib drug information
Keep checking

Other Drugs & Kefir

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

0Major
121Moderate
1Minor
2,707No known interaction
121 Moderate 1 Minor 2,707 No interaction
Moderate

121 interactions

Showing 60 of 121 moderate interactions — see all 121 on the Kefir page.

Minor

1 interaction

No interaction 2,707 drugs checked — show the list

We also checked Kefir against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,707 medications checked with no known interaction — see the full Kefir list.

See the full Kefir interactions page
See every supplement checked against Regorafenib, ranked by severity
Evidence & sources

Kefir References

The 10 references that drive our Kefir 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. St-Onge MP, Farnworth ER, Savard T, et al. Kefir consumption does not alter plasma lipid levels or cholesterol fractional synthesis rates relative to milk in hyperlipidemic men: a randomized controlled trial [ISRCTN10820810]. BMC Complement Altern Med 200 PubMed
  2. Murofushi M, Mizuguchi J, Aibara K, Matuhasi T. Immunopotentiative effect of polysaccharide from kefir grain, KGF-C, administered orally in mice. Immunopharmacology 1986;12:29-35. PubMed
  3. Shiomi M, Sasaki K, Murofushi M, Aibara K. Antitumor activity in mice of orally administered polysaccharide from Kefir grain. Jpn J Med Sci Biol 1982;35:75-80. PubMed
  4. Rimada PS, Abraham AG. Polysaccharide production by kefir grains during whey fermentation. J Dairy Res 2001;68:653-61. PubMed
  5. De Vrese M, Keller B, Barth CA. Enhancement of intestinal hydrolysis of lactose by microbial beta-galactosidase (EC 3.2.1.23) of kefir. Br J Nutr 1992;67:67-75.
  6. Athanasiadis, I., Boskou, D., Kanellaki, M., and Koutinas, A. A. Low-temperature alcoholic fermentation by delignified cellulosic material supported cells of kefir yeast. J.Agric.Food Chem. 1999;47(10):4474-4477. PubMed
  7. Rabl, W., Liniger, B., Sutter, K., and Sigrist, T. [Ethanol content of Kefir water]. Blutalkohol 1994;31(2):76-79.
  8. Fathi Y, Faghih S, Zibaeenezhad MJ, Tabatabaei SH. Kefir drink leads to a similar weight loss, compared with milk, in a dairy-rich non-energy-restricted diet in overweight or obese premenopausal women: a randomized controlled trial. Eur J Nutr. 2016;55(1) PubMed
  9. Turan I, Dedeli Ö, Bor S, Ilter T. Effects of a kefir supplement on symptoms, colonic transit, and bowel satisfaction score in patients with chronic constipation: a pilot study. Turk J Gastroenterol. 2014;25(6):650-6. PubMed
  10. Bellikci-Koyu E, Sarer-Yurekli BP, Karagozlu C, Aydin-Kose F, Ozgen AG, Buyuktuncer Z. Probiotic kefir consumption improves serum apolipoprotein A1 levels in metabolic syndrome patients: a randomized controlled clinical trial. Nutr Res 2022;102:59-70. PubMed

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 Kefir and Regorafenib Together: Common Questions

Is it safe to take Kefir with Regorafenib?
We do not list a known interaction between Kefir and Regorafenib. 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 Kefir and Regorafenib have any of the same side effects?
Yes — our sources link each of them separately to 3 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.
How was the Kefir and Regorafenib combination checked?
Interactions in our licensed database are recorded against drug classes. Regorafenib is filed under 2 classifications, and Kefir has documented interactions with 2 drug classes — none of Regorafenib'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 Kefir interact with any other medications?
Yes. Kefir has 122 documented drug interactions in our database — Regorafenib 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 Regorafenib interact with any supplements?
Yes. Regorafenib has documented interactions with 138 supplements in our database — Kefir is not one of them. The Regorafenib interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Kefir monograph Uses, safety profile, and every drug interaction in one place Regorafenib drug information The full plain-English guide to this medication Regorafenib supplement interactions Every supplement checked against Regorafenib, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 10 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Regorafenib and Kefir?

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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.