context: You may think of the flu as pretty harmless. Most of the time, it is. People typically recover after about a week or two without any lasting problems. But sometimes this illness can lead to serious complications that require emergency care. Every year more than 200,000 people in the U. S. wind up in the hospital because of the flu. Tens of thousands die. Infants, the elderly, and people with certain diseases or weakened immune systems are the most at risk. But a flu emergency can happen to anyone. So it's important to know the signs of trouble. Different strains of the influenza virus cause the flu. You get it when you inhale the germ or pick it up on your hands and then touch your eyes, nose, or mouth. Symptoms usually show up 1 to 4 days later. The flu can be hard to tell from a cold. But it usually comes on faster and is more severe. The so-called "stomach flu" isn't the same as influenza. The flu very rarely causes tummy trouble in adults. Normal flu symptoms include: High fever Headache Tiredness (can be extreme) Cough Sore throat Runny or stuffy nose Body aches Although flu vaccines can prevent certain strains, there's not much you can do after you get sick. If you take them within 48 hours after symptoms start, drugs like oseltamivir ( Tamiflu), peramivir ( Rapivab), and zanamivir ( Relenza) may ease some symptoms. You can also: Take over-the-counter painkillers like ibuprofen or acetaminophen, to relieve body aches, headache, and fever. Take over-the-counter antihistamines and decongestants to help with congestion. Drink lots of fluids. Get plenty of rest. Antibiotics don't treat the flu. They only work against bacteria, and the flu is caused by a virus. You might need antibiotics if you get a secondary infection in your ear, sinuses, or lungs (like pneumonia or bronchitis). Usually, you don't need to see the doctor if you get the flu. Your body will fight off the virus on its own if you get enough rest. But sometimes you -- or a family member -- may have serious problems as a result of the flu. Those more likely to get them include: Newborns and children up to age 5 (especially kids under age 2) People over age 65 Pregnant women People who live in long-term care facilities Caregivers People with chronic diseases like asthma, neuromuscular disease, heart problems, or lung disease People with a weakened immune system, either from a disease or its treatment Pneumonia, an infection of the lungs. If untreated, it can be life-threatening. Muscle inflammation (myositis) Central nervous system diseases Heart problems like heart attacks, inflammation of the heart muscle (myocarditis), and inflammation of the sac around the heart (pericarditis) Worsening of chronic medical conditions like congestive heart failure, asthma, or diabetes If you or your child get any of the following symptoms, get medical care at once. You may have a serious complication that requires treatment. Coughing up blood Croup, which causes a loud barking cough Wheezing Trouble breathing, shortness of breath, or rapid breathing Pain or pressure in the chest Confusion Bluish-colored lips or nails High fever Convulsions from fever (this usually affects children) Fever or cough that becomes severe or won't go away This serious illness occurs most often in children. It may follow infection with the flu or other viral diseases like chickenpox. It often happens after the child takes aspirin. Reye's syndrome affects the liver and brain. It's rare, but it can be life threatening. Symptoms include: Nausea and vomiting Confusion and delirium Listlessness Personality changes such as aggressiveness Convulsions Unconsciousness Because of its link to Reye's syndrome, never give aspirin to children or teenagers unless your doctor says it's OK. If you or a family member has any signs or symptoms of a flu emergency, call 911 right away or go to the emergency room. Don't wait.