A healthy diet, which consists of balance, variety and moderation is very important in keeping a strong immune system. Also, regular exercise stimulates the immune system. Another important factoring preventing colds and the flu is getting a sufficient amount of sleep. When a body is healthy and well rested, the immune system will come to its natural defense. Also important in the prevention and especially the treatment of the common cold is sufficient fluid replacement.
Fluids flush out harmful impurities, and help in the production of mucus.
The body uses more fluids than usual when fighting off a cold or the flu, which can leave it very dehydrated. Some suggested fluids are water, juice, tea and soup. Hot beverages are soothing for the throat and can help with decongestion. Also recommended is gargling with salt water, and inhaling moist air. Taking zinc lozenges and 500-1000 mg of vitamin C a day may also boost the immune system.