Human blood has been transfused for about 60-70 years. Over this time, the practice of blood transfusion has changed dramatically. One major change is the separation of blood into its various components. As a result, the patient can receive only the blood component in which he is deficient. In this way, the risk of side effects-particularly hepatitis-is lessened. This article briefly reviews the various blood products, the indications for their use, and some associated risks. These products include oxygen-carrying products, plasma products, blood products used to correct hemostatic defects, and immune globulin.