A part of the brain called the hypothalamus acts as the body's thermostat. When all is well in the body, the hypothalamus is set at the normal body temperature. Fever develops when the hypothalamus is set to a higher-than-normal temperature. This resetting of the hypothalamus is usually caused by small molecules called pyrogens in the blood. Pyrogens can come from outside the body (external) or can be produced inside the body (internal). External pyrogens include toxins (poisons) produced by infectious viruses or bacteria. Internal pyrogens include abnormal chemicals that are produced by tumors and proteins that are released during the normal response of the immune system. A fever is defined as a temperature 1° or more above the normal 98.6°. Mild or short-term elevations are common with minor infections. High fevers, with temperatures of 103° and above, can signal a potentially dangerous infection. There are several medications that can reduce body temperature by blocking the mechanisms that cause a fever. These so-called antipyretic agents include acetaminophen, ibuprofen and aspirin. All three of these drugs appear to be equally effective at reducing fever. However, since aspirin may cause or be associated with side effects, such as stomach upset, intestinal bleeding and (most seriously) Reye syndrome, we do not recommend using it to treat a simple fever. Ibuprofen use is approved for children 6 months of age and older; however, ibuprofen should never be given to children who are dehydrated or vomiting continuously. Ideally, the dose of acetaminophen should be based on a child's weight, not his age. The dose of ibuprofen should be based on baseline temperature and weight, not his age. However, the dosages listed on the labels of acetaminophen bottles (which are usually calculated by age) are generally safe and effective unless your child is unusually light or heavy for his age. Doctors often advise adults with mild to moderate fevers below 102° Fahrenheit to: Drink plenty of water and fruit juices to prevent dehydration (abnormally low levels of body water). Fluids help to cool your body and they replenish vital salts and minerals (electrolytes), which may be lost during vomiting or diarrhea. Eat light foods that are easy to digest! We urge you to find out more about fever today!