Arnica (Arnica montana) has been used for medicinal purposes since the 1500s and is still popular today. Applied to the skin as a cream, ointment, liniment, salve, or tincture, arnica has been used to soothe muscle aches, reduce inflammation, and heal wounds. It is commonly used for injuries such as sprains and bruises. As an herb, arnica is generally used only topically (on the skin) because it can cause serious side effects when taken by mouth. Oral homeopathic remedies do contain arnica, but they use an extremely diluted form that is not considered dangerous. If you have any question about whether you have the herbal or homeopathic form of arnica, talk to your doctor before taking it.

Arnica is a perennial that grows to a height of 1 - 2 feet with yellow-orange flowers similar to daisies. Stems are round and hairy, ending in one to three flower stalks, with flowers 2 - 3 inches across. Leaves are bright green. The upper leaves are toothed and slightly hairy, while lower leaves have rounded tips. It is native to the mountains of Europe and Siberia, and is cultivated in North America.

Fresh or dried flower heads are used in medicinal preparations.

• Arnica is used topically for a wide range of conditions, including bruises, sprains, muscle aches, wound healing, superficial phlebitis, joint pain, inflammation from insect bites, and swelling from broken bones.
• Homeopathic preparations are also used to treat sore muscles, bruises, and other conditions caused by overexertion or injury. Homeopathic doses are extremely diluted. They have no detectable amount of the plant in them and are generally considered safe for internal use when taken according to the directions on the label.

Arnica is available in topical creams and ointments. It is most commonly found as a tincture, which can also be used as the base for compresses and poultices. Arnica oil may also be used in topical preparations.

A number of homeopathic remedies are available in pill, topical, or injectable forms.

You should not take arnica by mouth without direct medical supervision, except in dilute form as a homeopathic remedy, because side effects may be severe (see "Precautions").

Homeopathic products should be used according to directions on the label or the advice of your homeopathic practitioner. Health care providers may give homeopathic preparations by injection.

When using arnica topically, never apply it to an open wound without a doctor's supervision.

Pediatric

Homeopathic preparations may be used to treat bruising, swelling, and trauma to soft tissues. Follow the dosage instructions on the product label or consult a licensed homeopath. Use only in homeopathic formulations. Don’t use the herb itself.

Adult

Topical preparations of arnica may be prepared as follows:

• Tincture: a 1:10 tincture prepared with 70% ethanol

• Creams and ointments: 20 - 25% tincture or a maximum of 15% arnica oil made from one part dried arnica flower head and five parts vegetable oil

• Compresses: tincture diluted 3 - 10 times with water

• Poultices: tincture diluted 3 - 10 times with water

• Mouthwash: tincture diluted 10 times with water (rinse but don't swallow)

Arnica is generally safe when used on the skin. However, using it for a long time may irritate the skin, causing eczema, peeling, blisters, or other skin conditions. Arnica should not be used on broken skin, such as leg ulcers. Also, people who are hypersensitive or allergic to the herb should avoid it.

Arnica is rarely used as an internal herbal remedy because it can cause dizziness, tremors, and heart irregularities. It may also irritate mucous membranes and cause vomiting. Large doses can even be fatal. Do not take arnica by mouth except under close supervision of your doctor. Homeopathic remedies, which use extremely small amounts of arnica, can usually be taken safely.

If you are pregnant or breastfeeding, avoid taking arnica, and ask your doctor before using it on your skin. Talk to your doctor before taking any medication, including herbs.

When used topically or in a homeopathic remedy, arnica does not interact with any conventional medications.

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