Whey, that amazing solution, was considered in the past as a waste byproduct. Recently, scientists had discovered that whey have powerful components; which are whey proteins. Nutritional value of whey proteins had been recognized many years ago. Whey proteins have different fractions, some of them are in large concentration like (β-lactoglobulin, α- lactalbumin, serum albumin, immunoglobulins and glycomacropeptide) and others are in low concentration, such as (lactoferrin, lactoperoxidase, lysozyme and proteose peptone component. Now a days, consumers become more aware of interest, nutritious, healthy foods, has driven much of the research into the healthful effects of whey protein and whey fractions. Whey proteins are magic, potent, promise and active components, which have many various nutritional and therapeutic benefits that encourage to search about them and collect the researches in a review paper to be a guide for all the requires and students. This review is focused on whey protein, its fractions and the therapeutic effect and their application in food processing and pharmaceutical field.