Signs of a serious allergic reaction to ibuprofen include difficulty breathing, hives and swelling of the throat, tongue, lips or face, according to Drugs.com. Immediate medical attention is necessary if weakness, chest pain, slurred speech or shortness of breath occurs. Problems with balance or vision also require immediate medical assistance.
Ibuprofen may cause bleeding in the stomach, which requires medical attention, states Drugs.com. Signs of bleeding in the stomach include coughing up blood or vomit that resembles coffee grounds and passing bloody, black or tarry stools.
Other possible side effects of ibuprofen that require medical attention include rapid weight gain or swelling, nausea, upper stomach pain and loss of appetite, notes Drugs.com. Ibuprofen may also cause little or no urination, dark urine, clay-colored stools or yellowing of the eyes or skin. After taking ibuprofen, some people may experience bruising, fever, sore throat or headache with a severe peeling, blistering and red skin rash. Other potentially serious side effects of ibuprofen include seizures, increased sensitivity to sunlight, chills and neck stiffness.
Common side effects of ibuprofen include ringing in the ears, dizziness, nervousness and mild heartburn, according to Drugs.com. Some people may experience a mild rash or itching after taking ibuprofen. Bloating, constipation, diarrhea and gas are also common side effects associated with ibuprofen.