Arnica cream is a topical treatment that is applied to the skin as a cream, ointment, liniment, salve, or tincture. It has been used to soothe muscle aches, reduce inflammation, and heal wounds. Arnica cream is commonly used for injuries such as sprains and bruises. The active chemicals in arnica may reduce swelling, decrease pain, and act as antibiotics. Arnica is most often used as a topical treatment for bruising, sprains, and muscle pain. It is important to note that arnica should not be taken by mouth unless it is used in homeopathic dilutions. If you have any questions about whether you have the herbal or homeopathic form of arnica, talk to your doctor.