Risk is the function of seriousness of the harm and probability that will occur . The risk can be physical,social,physiocologlcal, Economic. The risk-benefit ratio is a comparison between the risks of a situation and its benefits. The goal is to figure out whether the risk or benefit is most significant. Every medical procedure has risks associated with it, and some procedures that could be cause more harm than good. That’s how medical researchers figure out whether certain procedures are worth doing and what types of people will benefit. The risk-benefit ratio is useful for everyone. By actually thinking about the risks and benefits, we can make better decisions about our lives. To complete a risk-benefit ratio we need to know what are the risk how likely they are going to happen and the benefits associated with them. Increased risk should be accompanied by the probability of appropriately increased benefits. Everything should be-done to minimize the risks and to maximize the potential benefits, and to determine that the potential benefits to individuals and society are proportionate to, or outweigh, the risks.