Arnica (arnica montana) is applied to the skin for pain and swelling associated with bruises, aches, sprains, and arthritis. It is also applied to the skin for insect bites, muscle and cartilage pain, chapped lips, and acne. The active chemicals in arnica may reduce swelling, decrease pain, and act as antibiotics. Arnica is perennial that is native to mountainous Europe and has a yellow Daisy like flower.