Pain after surgery. Most research shows that taking homeopathic arnica by mouth slightly reduces pain after surgery. In some cases, homeopathic arnica has been used together with an arnica ointment from 72 hours after surgery for 2 weeks.
Arnica is applied to the skin for pain and swelling associated with bruises, aches, and sprains applying an arnica ointment has been shown to reduce bruising when applied twice daily for 2 weeks.
Broken skin: Don't apply arnica to damaged or broken skin.