The dream vacation you’ve planned for over a year is a few days away and you’ve got the worst flu of your life. Or, maybe you’ve been away from home on a two-week business trip and all you want is your own bed – but you’re finding it nearly impossible to get out of the hotel bed because you’re so sick. It can be tempting to try to show a little grit and get on that flight no matter what, but there are sometimes you just shouldn’t fly. When your health is at risk – or you’re putting the health of your fellow passengers at risk – knowing when to reschedule is important.

When It’s OK to Fly

There are times when you’re not feeling 100 percent but it’s still OK to fly. This includes:

• Traveler’s diarrhea: The dreaded Montezuma’s Revenge is definitely uncomfortable and potentially embarrassing. However, you won’t be putting your health or the health of your fellow passengers at risk if you fly. This one is your call. If you are having stomach issues, taking an over-the-counter anti-diarrheal medication can help you make it through the uncomfortable hours in economy class.
• You have a sinus infection or cold: If you’re feeling sinus pressure and cold symptoms at sea level, expect them to get worse once you’re at altitude in the airplane. However, there are no restrictions on flying with a cold, but you should take some precautions to protect yourself and others. Take a decongestant before flying, cover your mouth and nose when coughing or sneezing, and bring hand sanitizer and disinfectant wipes to clean your area before leaving.
• You’re hungover: They say “what happens in Vegas, stays in Vegas,” unless of course, it’s a hangover. That’s coming home with you if you’ve had too much fun the night before your flight. You can still fly but you’ll likely feel terrible. Do your best to rehydrate your body before the flight and stay hydrated while you’re in the air. If your stomach can handle it, eating can help with the queasy feeling.
• You’re injured: If you have a broken bone or a sprain, you can still fly. Let the airline know beforehand if you need a wheelchair or other special assistance to help with your mobility in the airport.

When You Should Not Fly

Don’t fly when you’re dealing with any of the following illnesses:

• You’ve had surgery recently: Doctors recommend waiting 10 to 14 days after surgery before flying. These guidelines are especially important to follow if you’ve had abdominal, chest, head or throat surgery, since pressure changes during a flight can cause complications. Abdominal surgery also puts you at greater risk for clotting, which can be made worse by flying.
• You have a high fever: A fever below 100 degrees Fahrenheit is fine, but anything higher should keep you grounded, according to the Centers for Disease Control. If your fever is accompanied by other symptoms like vomiting and diarrhea, you should cancel your trip.
• You have the flu: Remarkably, many people fly with the flu. If you do this, you’re putting your fellow passengers at risk since a cough or sneeze can spread the flu virus as far as six feet away. If you have obvious symptoms of the flu, don’t be surprised if the gate agent denies boarding.

As a general rule of thumb, let your body and common sense be your guide about when you’re too sick to fly. If you have travel health insurance, you’ll be able to reschedule your trip and find the medical treatment you need if you’re stuck somewhere away from home.