The correct dosage of ibuprofen for adults depends on why the medication is being used. The recommended adult dosage for mild to moderate pain or fever is 200 to 400 milligrams every four to six hours, according to Drugs.com. Dosage for adults with arthritis is 400 to 800 milligrams.
Regardless of the reason a person is taking ibuprofen, an adult's total dosage should not exceed 800 milligrams per dose or 3,200 mg per day, warns Drugs.com. Taking too much ibuprofen can cause damage to the stomach and intestines, including internal bleeding and perforations. The most common ibuprofen side effects are abdominal pain, bloating and diarrhea.