Biophoton emission is the spontaneous emission of ultraweak light emanating from all living systems,including man.It is an intrinsic property of living things and contains a plenty of biological information.The emission is linked to the endogenous production of excited states within the living system.It has been known to be a good mediator for investigating physical and pathological characteristics of the system.The detection and characterization of human biophoton emission has led to suggestions that it has potential future applications in medicine.The published material is presented and its relations to health and disease are reviewed in this paper.