What is the biochemistry behind the use of Arnica for muscle pain/ache relief? by Connie b. Dellobuono

Answer by Connie b. Dellobuono:

It cleans the blood. Our lympathic system (also helps detox our blood, as we massage our lymps – armpit and thighs).
http://herbpathy.com/Uses-and-Benefits-of-Arnica-Cid1581
Other herbs that can clean the blood are: ginger, turmeric, massage oil of coconut oil and fresh ginger, lemon grass, Vit C and sulfur rich foods.

What is the biochemistry behind the use of Arnica for muscle pain/ache relief?