Scientific Name: Arnica
Other Names: Arnica montana, Leopard's Bane, Mountain Snuff, Mountain Tobacco, Wolf's Bane, Wolfbane

Who is this for?

Uses

Note: Arnica is widely available―especially in Europe―as both an herbal product and a homeopathic preparation. Homeopathy is a form of alternative medical treatment that is practiced more in other countries than in the United States. In homeopathy, individuals take a very small amount of a natural product that in higher doses would produce symptoms similar to the condition being treated. In small studies done in Europe, oral doses of homeopathic arnica lessened swelling for some individuals after knee surgery. It is important to note, however, that herbal arnica generally consists only of plant material while homeopathic arnica has been mixed with inactive ingredients. Herbal arnica is, therefore, usually much stronger than homeopathic arnica. Taking herbal arnica by mouth is strongly discouraged because it may result in potentially dangerous increases in blood pressure.

Most often, herbal arnica is used topically to relieve the pain and inflammation of soft-tissue injuries such as boils, bruises, hemorrhoids, and sprains. Inflammation is a response to irritation, injury, or infection. It usually includes pain, redness, and swelling in the area of the damage and it can occur within body tissues as well as on the surface of the skin. In a study of 204 Swiss patients with arthritis in their hands, an arnica gel was about equally as effective at controlling pain as a 5% ibuprofen gel. The type of base used to make the gel may alow more of arnica’s active chemicals and potentially harmful chemicals to enter the skin. More research is needed, therefore, before arnica can be recommended for topical use.

Due to possible antiseptic and slight antibacterial properties, topical arnica has also been used to treat acne, insect bites, and minor skin wounds. It may be effective, as well, in mouth rinses to control some bacteria commonly found in the mouth. Scientific studies show little effectiveness, however, for topical arnica in preventing or relieving bruising or in relieving muscle soreness among long-distance runners. A recent analysis of eight previously published studies found little evidence that topical arnica preparations were more effective than placebo (preparations with no active ingredients) for treating any soft-tissue conditions.

If it is swallowed, arnica may cause a rapid increase in blood pressure, which can damage the heart. This possible risk may occur in individuals with no previous history of heart problems, but it may be especially hazardous for individuals with heart conditions or for those who take medications to control high blood pressure. While the oral use of arnica is not recommended for any individual, those with heart conditions should be particularly careful to avoid taking it.

Precautions

Applying arnica topically for prolonged periods, especially on the same part of the skin, can result in irritation at the place where it is applied. If an arnica preparation that is too strong is used, blistering, scarring, and even permanent skin damage may result. Arnica can also be irritating to the eyes, nose, and other mucous membranes. Children and elderly individuals generally have skin that is more sensitive, therefore, they may be more likely to have skin reactions from applying arnica.

Possibly, small amounts of topically applied arnica may be absorbed through the skin. Very little information is available on how arnica might affect a developing fetus, an infant, or a small child. Therefore, even topical use of arnica is discouraged during pregnancy, while breast-feeding, or during early childhood.

Individuals who must handle arnica plants frequently have been known to develop contact allergies to it. Individuals who are allergic to plants of the daisy family may also be allergic to arnica.

What side effects should I watch for?

Major Side Effects

Severe side effects―including heart rhythm changes, high blood pressure and shortness of breath―can result if arnica is taken by mouth. Muscle paralysis has also been associated with its use, and ingesting very large oral doses of arnica has even resulted in death. Therefore, it is not recommended that arnica be taken by mouth.

Although topical arnica is used on the skin to decrease pain and inflammation, it can irritate raw skin seriously; therefore, it should not be used on open sores or large, deep wounds. If it is applied to the skin too long, too often, or in concentrations that are too high, arnica can cause allergic dermatitis that may leave permanent scarring.

Less Severe Side Effects

When arnica is taken orally, diarrhea, stomach pain, and vomiting may occur. It may also irritate mouth, throat, and gastrointestinal tissue. In one study, a significant number of individuals who took large oral doses of arnica developed severe stomach inflammation.

Handling arnica plants or applying arnica products may result in:

• Blistering
• Irritated skin
• Itching
• Redness

What interactions should I watch for?

Although no interactions have been reported between topical arnica and drugs or herbals, arnica's possible negative effects on the heart and its potential to raise blood pressure make it unsuitable for use by individuals who take drugs to control heart conditions or high blood pressure.

Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how arnica interacts with drugs, other herbals, and foods and the severity of those interactions, please use our Drug Interactions Checker to check for possible interactions.

Should I take it?

Small perennial bushes with daisy-like yellow flowers, most arnica species are native to Europe and eastern Asia. They also grow in the mountains of Canada and the northern United States. For medical use, the flowers of the plants are collected in the summer and dried. The dried flowers are used externally in liniments, washes, and ointments. Other products that contain arnica include cosmetics such as shampoos and other hair grooming products. In the United States, small quantities of arnica are approved for use as a flavoring in some bakery items, beverages, and gelatin-based desserts. Dried arnica roots have been used in some folk remedies, but preparations of arnica root are not currently recommended for any use. Because arnica is an endangered species in many areas of the world, it may be difficult to obtain. Supplements claiming to contain it may be made from other, similar plants.

Dosage and Administration

Note: Taking herbal arnica by mouth is not recommended because it may cause a sudden, potentially dangerous increase in blood pressure. In addition, it contains varying amounts of chemicals known as sesquiterpene lactones that can cause possibly serious irritation of the mouth and gastrointestinal system.

Topical arnica preparations should contain no more than 15% of arnica oil or 25% of arnica tincture, because higher strengths are more likely to irritate the skin. Application should be limited to once or twice a day and arnica should be used only for as long as needed.

Summary

Although it is approved in very small amounts as a flavoring agent, arnica is not safe when taken orally. Herbal arnica should not be taken by mouth.

As a topical agent, arnica may help to relieve the pain and swelling of sprains, bruises and similar injuries. Its slightly antiseptic and antibacterial properties may alleviate acne and minor skin abrasions, but it should not be used in high concentrations, for prolonged periods, or on raw skin.

Risks

If it is taken internally, arnica can affect heart function, damage mouth tissues, cause or worsen high blood pressure, produce shortness of breath, and irritate the esophagus, stomach, or intestines. Very large amounts taken by mouth can cause death.

When used topically for long periods, in high concentrations, or on raw skin; arnica can cause major blistering, irritation and scarring. Long-term use may result in allergic dermatitis.

Side Effects

Oral arnica may cause:

• Heart damage
• Irritated mucous membranes
• Stomach irritation
• Sudden increases in blood pressure

Topical arnica products may cause:

• Contact allergies
• Dermatitis
• Irritation at the site of application

Interactions

No interactions between topical arnica and prescription drugs, non-prescription drugs, other herbal products or foods have been reported. People who take drugs for heart conditions, however, should not use arnica without a doctor's consent.

Last Revised May 3, 2007

References

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Last Revised May 3, 2007

Note: The above information is not intended to replace the advice of your physician, pharmacist, or other healthcare professional. It is not meant to indicate that the use of the product is safe, appropriate, or effective for you.

In general, herbal products are not subject to review or approval by the U.S. Food and Drug Administration (FDA). They are not required to be standardized, meaning that the amounts of active ingredients or contaminants they contain may vary between brands or between different batches of the same brand. Not all of the risks, side effects, or interactions associated with the use of herbal products are known because few reliable studies of their use in humans have been done.

This information is provided for your education only. Please share this information with your healthcare provider and be sure that you talk to your doctor and pharmacist about all the prescription and non-prescription medicines you take before you begin to use any herbal product.

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