Ibuprofen is generally not recommended for children younger than 6 months of age, because the medication has not been extensively studied in younger infants. It is probably safe even for younger infants and may be recommended by your doctor on occasion.
Children with a known or possible allergy to ibuprofen or aspirin should not take this medication without speaking first to a physician. Children with kidney disease or chickenpox should not take ibuprofen without first talking with a doctor. Children who are taking oral steroids or other non-steroidal antiinflammatory medications (such as naproxen) should not take ibuprofen without first consulting with a physician.
Ibuprofen may be taken as often as every 6 hours. In general, children should not take more than 3 doses of ibuprofen per day.