Fluids, tylenol (acetaminophen) . Under 2 mo call your doctor for t>100.4. After 2mo assure good fluid intake and use tylenol (acetaminophen) if baby is grumpy. Low grade temperature can be monitored without meds. Ibuprophen should be avoided under 6 mo. For fever with concerning change in activity or appearance, contact your physician. If baby seems happy and playful, taking fluids well, you can monitor at home for a few days.
Acetaminophen. Fever is almost always a sign of infection, but whether you should be concerned depends on other factors (height of fever, duration, patient's age and other symptoms). Fever can be treated with Acetaminophen (if > 2 months) or Ibuprofen (if > 6 months) and the dosing is weight-based. Speaking to your physician and knowing when to be concerned and when to treat a fever at home is half the battle.