The European Medicines Agency says that arnica is approved to help relieve bruises, sprains and localised pain.
4 It has an anti-inflammatory effect inside the body and supports tissue repair, according to a 2016 study in PLoS One. The researchers say one way arnica may work is by interacting with the genes responsible for repairing cells.
5
A 2010 study by Northwestern University, Chicago, found that an ointment of 20% arnica applied twice a day for two weeks faded laser-induced bruises more quickly than the placebo.6