The human body has a thermostat which helps us to regulate our body temperature. The normal body temperature is between 36.5°C and 37.5°C. With infection or other illnesses, various chemicals are released in our body. This re-adjusts the thermostat, resulting in fever. A body temperature of 38.5°C a nd above is considered high fever. Consult your doctor when your child: Is feeding poorly, vomiting or lethargic. Is very young, especially less than 3 months old. Has difficulty breathing . Is drowsy. Looks sicker than previously. Has abdominal pain and discomfort. Has rash. Has decreased urine output.