More than 100 viruses can cause colds, the world's most common illness, so few people escape being exposed to at least one of them. In the United States, most people average about three colds every year.
  
Once it enters the body through the nose or throat, the cold virus begins to multiply, causing any of a number of symptoms: sore throat, sneezing, runny nose, watery eyes, aches and pains, mild fever, nasal congestion and coughing. A cold usually lasts a week or two.

The best way to treat a cold is to take a mild pain reliever, avoid unnecessary activity, get as much bed rest as possible and drink plenty of fluids, especially fruit juices. Over-the-counter cough and cold remedies may relieve some of the symptoms, but they will not prevent, cure or even shorten the course of the illness.
   
While there is no vaccine to protect you from catching a cold, there are ways to lessen your chances of coming down with the illness. Keep up your natural resistance through good nutrition and getting enough sleep and exercise. Turn your thermostat down and keep the humidity up in your home. Dry air dries out the mucous membranes in your nose and throat and causes them to crack, creating a place where cold viruses can enter your body. Avoid direct contact with those who have colds and wash your hands frequently.