"Even if you don't feel bad but have a contagious disease that could infect coworkers, such as conjunctivitis or a bacterial sinus infection that has not been treated with antibiotics for 24 hours, you should stay home," he says. "You also shouldn't be around others if you have a fever above 102 degrees, diarrhea, unexplained rash or vomiting."
So if you only have a cold, what should you do to get better? Hit the sack and stay there between eight and 10 hours a night. "People have colds who get only six hours of sleep a night are turning what could have been a three- to five-day illness into a seven- to 10-day sickness."
All that sneezing and coughing is your body's way of shedding -- and spreading -- the cold virus.
"But cold germs are everywhere so your co-workers are as likely to pick up the illness from the next guy as they are from you," says Dr Mengel. "You'll get well quicker, though, if you take it easy because rest helps the immune system focus on the infection. If you're up and active, your body uses energy for other things than getting well."
Few follow that advice, Dr Mengel admits. "Nobody has time to do that so at least try not to cough and sneeze on people."
If you feel so rotten that you won't be able to focus on work, stay home and rest because you'll wind up having to re-do what you messed up anyway.
Turn to the advice Mom offered: drink plenty of fluids -- including hot tea and chicken soup -- and use a humidifier to add moisture to the air and help you breathe easier. If you want to relieve congestion and sinus pressure, you can take over-the-counter decongestants.
Antibiotics fight bacterial infections and don't make colds, which are caused by viruses, go away.
About a third of those who get colds wind up with bacterial ear or sinus infections that can be treated with antibiotics, Dr Mengel adds.
"If you feel lousy for two or three days, then feel better, then feel worse, you may have developed a secondary infection so you should see your doctor," Dr Mengel says. "If you have colored sputum, a high fever or shortness of breath, you also should call your doctor."