Herb & supplement monograph

Rehmannia Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated June 2026

What is this page for?

First and foremost: how Rehmannia interacts with medications. The heart of this page is the interaction list — every drug Rehmannia is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Rehmannia is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Rehmannia Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Rehmannia drug interaction appears low for most people, though two medication groups deserve awareness. None of the listed interactions are rated major, and all of them rest on animal or laboratory research rather than studies in people.

Interactions deserving the most attention

The combinations that matter most involve diabetes medications and blood pressure medications. Animal research suggests rehmannia may lower blood sugar, so pairing it with diabetes drugs could theoretically push blood sugar too low. Similar research suggests it may lower blood pressure, partly by acting on a system the body uses to regulate it, which could add to the effect of blood pressure drugs. Because both blood sugar and blood pressure are closely monitored, even a modest added effect could matter for some people.

What the rest of the list means

The long list of interacting medications comes almost entirely from these two broad drug groups, so the number looks larger than the actual concern. Every interaction here is theoretical, drawn from animal or lab findings, and none has been confirmed to cause meaningful problems in people.

Check your medications against Rehmannia

Based on HelloPharmacist’s Rehmannia interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Rehmannia

258 medications have a known interaction with Rehmannia, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Rehmannia using our pharmacist-reviewed interaction data.

AI summaries are generated from our Rehmannia interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Rehmannia combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Rehmannia affects

Every type of medication (drug category) Rehmannia is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 2 drug categories Rehmannia interacts with

Antidiabetes DrugsAntihypertensive Drugs

Antidiabetes Drugs

Theoretically, rehmannia might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research shows that rehmannia may have hypoglycemic effects.

Likelihood Possible Evidence D

Antihypertensive Drugs

Theoretically, rehmannia might increase the risk of hypotension when taken with antihypertensive drugs.
Animal research shows that rehmannia may have hypotensive effects. Laboratory research shows that formulations of dried and processed rehmannia root inhibit angiotensin-converting enzyme (ACE).

Likelihood Possible Evidence D

Monograph

Rehmannia: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed June 2026 ·

The bottom line

Rehmannia is a root used for centuries in Traditional Chinese Medicine, often to 'tonify' the kidneys and support energy or blood health. Human evidence for most modern uses is limited, so it should be viewed as unproven rather than reliable. Talk with a pharmacist or doctor before trying it, especially if you are pregnant, breastfeeding, or take other medicines.

Scientific name: Rehmannia glutinosa
Family: Orobanchaceae
Part used: Root (raw or steam-prepared)
Common forms: Dried root, decoctions/teas, capsules, tinctures, and ingredient in multi-herb formulas

People commonly use it for

Kidney and adrenal support
Anemia and blood building (traditional)
Inflammatory conditions
Allergies
Fatigue and aging-related complaints

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally used in traditional medicine, but human safety data are limited and quality varies between products.

PregnancyInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Rehmannia comes from the root of Rehmannia glutinosa, a flowering plant native to China and parts of East Asia. It is one of the most commonly used herbs in Traditional Chinese Medicine (TCM), where it is often called Di Huang.

The root is used in two main forms. The raw or dried root is considered 'cooling,' while the steam-prepared (sometimes wine-processed) root is considered 'warming' and is used for different traditional purposes. Rehmannia is rarely used alone; it usually appears as part of multi-herb formulas.

Today people take it as dried root, teas or decoctions, capsules, and tinctures, often for energy, kidney support, or as a 'blood tonic.'

How it works

Rehmannia root contains several types of compounds that researchers have studied, including iridoid glycosides (such as catalpol), sugars called polysaccharides, and other plant chemicals. In laboratory and animal studies, some of these compounds appear to have anti-inflammatory and antioxidant activity, and may affect the immune system or blood sugar.

Researchers have also looked at whether Rehmannia influences hormone-related and adrenal pathways, which may be the basis for its traditional 'tonic' uses. However, these mechanisms are mostly based on cell and animal research and have not been clearly proven to produce the same effects in people.

Effectiveness

Does Rehmannia work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 9 uses evaluated

1 Possibly effective 8 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Possibly Effective Chronic kidney disease (CKD)