Healthy sinuses are lined with a moist, mucus-producing membrane, and they normally drain nearly a quart of moisture daily, humidifying the air you breathe in the process. If the sinuses become infected, swollen, and inflamed--say, following a cold--they can't drain properly, and you're miserable. (Your chances of developing a sinus infection increases if you have hay fever, if you smoke, or if you have a nasal deformity.)

Symptoms include:

Head congestion
Nasal congestion and discharge (usually yellowish green)
Pain and tenderness over the facial sinuses Pain in the upper jaw
Recurrent headache that changes with head position and disappears shortly after getting out of bed
Fever

A cool mist humidifier can help relieve sinus misery. Super-moist air helps to thin out the thick sinus secretions and loosen the mucus that has accumulated while your sinuses were out of order. Warm compresses placed over the sinus area relieve discomfort still further.

Other measures that can help include:

Drinking plenty of fluids to keep secretions thin and flowing.
Taking aspirin or acetaminophen for pain.
Using over-the-counter oral decongestants. (Note: Use nose drops cautiously, if at all.
colds are transmitted by the spread of mucus on the hands of someone who has a cold.
Repeated use of nasal decongestants creates a dependency--your nasal passages "forget"
how to work on their own and you have to continue using drops to keep nasal passages clear.
So never use them for more than three days. And to avoid picking up germs, never borrow
nose drops from others.)

If your symptoms persist despite home remedies, see a doctor. Sinus complications can be serious. You may need a prescription antibiotic and decongestant to clear the infection. (Severe cases may require surgery to drain the sinuses.)