Arnica most often is made into a cream or ointment that can be rubbed into the skin. It can be used to treat bruises, muscle strains, arthritis, bunions, joint dislocations, and virtually any other type of problem that occurs to the muscular and skeletal systems. Arnica is also a good treatment in some cases to treat inflammation of the throat and the mouth. However, it’s important that you don’t take arnica internally without supervision.But don't let the side effects scare you. Arnica does a great job of helping wounds heal in the joints and muscles. Researchers think it actually helps to remove clotted blood from the affected areas and help circulation improve. When you have a lot of circulation around the injury, healing can happen more quickly and easily. Arnica can have some side effects such as vomiting and increased heart rate that are dangerous for the body.