Long favored by mothers for their sick children, chicken soup has been tested by scientists. They found it relieves cold and flu symptoms by acting as an anti- inflammory agent, inhibiting movement of the immune system cells that are involved in the body's inflammatory process. The soup helps relieve congestion by temporarily speeding up mucus movement through the nose. That limits the time viruses have contact with the nasal lining.

And the soup doesn't have to be homemade. Researchers found many canned soups work just as well, but they may have high sodium content.