“…During natural metabolic processes taking place in diverse living organism, permanent and spontaneous ultraweak biophoton emission has been observed without any external excitation [1,9,29,36,37,49,50,54,66,70,77,83,89,96,97,107]. The emergence of biophotons is due to the bioluminescent radical and non-radical reactions of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS), and involves simple cessation of excited states [52,61,102]. The main source of biophotons derives from the oxidative metabolism of mitochondria [94].…”