If you have the flu, you should stay home until your fever has been gone for 24 hours without fever medication. If you have a cold, it really depends on how you feel. If your symptoms are bad enough to interfere with your job performance, you're coughing a lot, or you just feel bad, stay home and rest. Whether you have the cold or flu, remember that you’re contagious. So your co-workers may actually thank you for staying home.