It is observed that vitamin C has similar structure with that of melatonin, from chemistry point of view compounds of similar structure has the same chemical properties but different physical properties. This is a research on the radioprotective effect of vitamin C / glutathione and some free radical scavengers. Radiation in human body is a process where energy emitted by one body travels in a straight line through a medium or through space. It is energy in the form of particles or waves. It is emitted naturally in sunlight and is also made by man for use in X-rays, cancer treatment, and for nuclear facilities and weapons. Vitamin C or L-ascorbic acid, or simply ascorbate (the anion of ascorbic acid), is an essential nutrient for humans and certain other animal species. The biological role of ascorbate (vitamin C) is to act as a reducing agent, donating electrons to various enzymatic and a few non-enzymatic reactions. This research contains the biological function of vitamin-C, the mechanism of biological damage by ionizing radiation on DNA, biological damage by direct mechanism biological damage by indirect mechanism, the radio protective effect of vitamin C, the radio protective effect of glutathione and other myriad enzymes and the scavenging effect of myriad enzymes.