Arnica (Arnica Montana) is a homeopathic anti-inflammatory that may be used for traumatic injury, bruises, strained joints, muscles, ligaments, tendons & backache etc. Alternatively arnica is probably best known as a pain relieving oil that counteracts inflammation and reduces swelling and discoloration on bruises. When blood vessels are broken, blood escapes and comes to rest in the surrounding tissue. This trapped blood is responsible for black and blue bruise marks. Arnica reduces these marks by helping the body reabsorb this trapped blood.