To my knowledge, there is no arnica spray on the market. The forms I mentioned are for external use only, to speed the healing of bruises , sprains , soreness and swelling, and to relieve arthritis, muscle and cartilage pain. It smells good and feels good when it's massaged in. This is the most effective way to use this herb. I've noticed lately that arnica is an ingredient in some commercial sports medicines.
Arnica compresses are another way to relieve musculoskeletal pain.
Simply mix a tablespoon of arnica tincture in a pint of spring, distilled or filtered water. Dip a gauze pad or sanitary napkin in the mixture, then put it on the arthritic joint or bruised area. Arnica is poisonous if it gets inside the body. I usually recommend the 30X dilution as a first aid treatment for trauma. Pour four pills into the cap of the bottle, then toss them into your mouth, under your tongue.