When should I call my doctor?

Most colds just need time to clear up, but you should contact a doctor if you have a severe cough, a high fever that won't go away, or you've been sick for a week. "For somebody otherwise healthy, your doctor will probably say, 'Yep, you have a cold. Go home and take care of yourself,'" says Cranshaw. "Anybody who is really miserable — getting worse, not able to keep food or fluids down, or with a fever over 101 degrees — should talk to a doctor or nurse. I bet they'll appreciate hearing from you."

  One last note: even though you may start to feel better, you could be contagious for at least 24 hours after a fever disappears. "You shed those viruses even after the fever is gone," Cranshaw says. So stay home for one extra sick day, and you may keep others from getting sick, too.