Is Arnica Safe With Lisinopril?

In our latest question and answer, our pharmacist discusses whether or not arnica can safely be used with lisinopril.


I have been taking arnica since a surgery I had months ago. I have osteoarthritis and fibromyalgia and this took all of my pain away. However, now I'm on lisinopril for blood pressure. Can I take arnica and lisinopril together? I stopped taking arnica montana and the pain is back full force.

Asked by Penny On Jan 09, 2023

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Jan 10, 2023
Last updated Apr 19, 2024

Key points

  • There is no known drug interaction between arnica and lisinopril.
  • Most over-the-counter arnica products are homeopathic preparations, which are very unlikely to have clinically significant drug interactions due to the small amounts typically utilized.


Thanks so much for reaching out! Arnica, a commonly used herbal ingredient in a variety of over-the-counter products, is considered safe to use while taking lisinopril.

Although data regarding dietary supplements and herbal ingredients are generally sparse, studies have only really documented arnica having a potential interaction with anticoagulant and antiplatelet drugs, such as:

However, and this is an important point, even though arnica may have mild blood-thinning effects, interactions with it are quite unlikely since it is most often used in homeopathic preparations and only very small amounts of arnica are used.

Does Arnica In Over-The-Counter Products Have Drug Interactions?

As mentioned, arnica is most commonly utilized in homeopathic preparations, which follows the principle of 'like cures like', meaning a substance that would cause certain symptoms in a healthy person can be used to treat similar symptoms in someone who is sick. An example here would be a homeopathic onion extract preparation being used to treat watery eyes.

Homeopathic preparations are often highly diluted and those who practice homeopathy believe that the remedies work by stimulating the body's own healing processes.

If we look at an oral arnica product from a popular brand, Arnicare, we can see that the labeled strength is '6C':

Arnica 6C

The "6C" describes the dilution factor of this product and indicates the number of times the substance has been diluted by a factor of 100. So in this case, arnica has been diluted by a factor of 100 six times and the resulting amount of arnica in this product is extremely small. It's a ratio of 1:1,000,000,000,000 (1:1X10-12).

Such a small amount is extremely unlikely to cause any drug interactions.

Now, it must be said that topical arnica preparations typically contain far more arnica than oral preparations.

Sticking with the same brand, Arnicare, their topical gel is a 1X dilution.

Arnicare Gel

A 1X dilution is certainly more concentrated than the oral preparation I wrote about above. 1X means it has been diluted by a factor of 10 one time, so a ratio of 1:10.

Still, even with this amount, it is unlikely to cause drug interactions and since it is being applied topically, there would be far less absorption of the drug compared to it being given by mouth.

I do want to point out that topical arnica has been shown in some studies to be effective for certain types of pain, so I don't want to come off as discounting it. For example, one study found that topical arnica was as effective as ibuprofen in treating osteoarthritis for some individuals.

I'm just pointing out that it is unlikely to have drug interactions when used in the amounts you typically see in over-the-counter products.

Nevertheless, like always, be sure to let your doctor know of all the medication you take so you can be appropriately monitored (especially if you are taking drugs that thin the blood due to some evidence showing arnica having blood thinning effects).

Final Words

I hope this answer helped!

Based on all the information I could find, it seems like arnica is safe to take with lisinopril. Aside from the fact that arnica likely doesn't have clinically significant drug interactions to be concerned about due to the small amounts used in over-the-counter products, studies also don't show it causing drops in blood pressure, so is likely safe with blood pressure medications, like lisinopril.


  • Choosing between NSAID and arnica for topical treatment of hand osteoarthritis in a randomised, double-blind study, PubMed
  • Arnicare Product Page, Arnicare
  • Clinical Trials, Potential Mechanisms, and Adverse Effects of Arnica as an Adjunct Medication for Pain Management, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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