Arnica, Natural Medicine

Publication Date: 
Thu, 09/27/2012
By: Alere Staff

Arnica is a natural product used in both food products and for medicinal purposes. Arnica is a plant that displays a yellow daisy-like flower throughout July. Preparations made from the flowering heads have been used in homeopathic medicine for hundreds of years. It is popular in Europe with over 100 drug preparations are made from the plant. Arnica is a perennial that is protected in parts of Europe.1

Interactions with warfarin?

Arnica is known to stimulate blood circulation and can raise blood pressure, especially in the coronary arteries. This natural compound contains coumarin derivates, which increases the bleeding risk and can inhibit platelet aggregation. There is some concern that arnica might potentiate the effects of anticoagulant and antiplatelet drugs and possibly increase the risk of bleeding.3

As always, discuss your diet, medications, and any natural homeopathic remedies with your doctor. Increasing testing frequency is recommended when starting or stopping any dietary supplement, including vitamins. Home INR monitoring can help improve your control of warfarin. More frequent testing, typically performed by patient self testing, is a valuable tool for detecting rises and falls in INR values and enable you to work with your clinician to make any adjustments to diet or medication dosing.3 Go to the Getting Started page for more information about testing your INR at home.


  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  2. Heck, AM, DeWitt, BA, Lukes, AL. Potential interactions between alternative therapies and warfarin. American Journal of Health-System Pharmacy, Vol 57, Issue 13, 1221-1227.
  3. Center for Medicare and Medicaid Services. Decision Memo for Prothrombin Time (INR) Monitor for Home Anticoagulation Management (CAG-00087R) [Memorandum]. 2008. Baltimore, MD.