A short-term rise in body temperature that's often caused by an infection.

Get plenty of rest. Keep the room temperature cool. Drink water and clear broth. Give a baby under 6 months with a fever only breast milk or formula. Adults who have discomfort from a fever can take acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others). These medicines are available in children's and infants' versions. Ask a child's pediatrician how much medicine to give. Don't give aspirin to children, as it may cause a rare, serious condition.

See a health care professional right away if:

• A baby younger than 3 months has a rectal temperature of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher.
• A baby between 3 and 6 months has a temperature higher than 102 degrees Fahrenheit (38.9 degrees Celsius).
• A baby between 7 and 24 months has a temperature higher than 102 degrees Fahrenheit (38.9 degrees Celsius).
• Any baby has a fever with symptoms such as cough, diarrhea or sluggish behavior.
• Any child has a fever with seizures, severe headache, confusion or other concerning symptoms.
• Any child has a fever after being left in a hot car.
• An adult has a fever with symptoms such as a bad headache, rash, chest pain, trouble breathing or stiff neck.