Children’s Motrin ibuprofen oral suspension, berry flavor liquid, 4 fluid ounces (118 mL). Help your kids bounce back by relieving their pain or fever with Children’s MOTRIN. For high fever, nothing works faster or lasts longer among OTC brands. Lasts up to 8 hours. Active ingredient: ibuprofen (NSAID/fever reducer/pain reliever) 100 mg/5 mL.