The article provides information related to blood transfusion. Allergic transfusion reactions (ATR) and febrile nonhemolytic transfusion reactions (FNHTR) have plagued the administration of blood since the early 20th century. FNHTRs and ATRs are usually not life threatening, they remain a challenge for both patients and physicians. FNHTR are common and are diagnosed in patients with a transfusion associated temperature increased at one degree Celsius.