Arnica is probably the most well known remedy in Homeopathic medicine, where it is highly regarded following stress. Combined with Witch Hazel and MSM, NAF Arnica Gel has a cooling and soothing effect on joints and muscles. NAF Arnica Gel should be massaged into areas that show 'bruise-like' soreness after muscular exertion, or following a knock or blow, such as a kick from another horse.