Sitting in the aisle seat on an aeroplane may give you easy access to the loo and some extra space to stretch your legs, but it also makes you more exposed to germs.
A scientist at the University of Arizona found that aisle seats have a significantly higher level of bacteria on them than window seats.
The germy chairs are thought to be the result of people using aisle seats to keep their balance when walking to and from the toilets.
Microbiologist Dr Charles Gerba collected swabs from areas people touch most frequently on more than 20 flights, including taps, sinks, toilet handles, arm-rests, trays and overhead lockers.
He found aisle seats carried higher levels of bacteria than middle or window seats.
Dr Gerba conducted the experiment to confirm the findings of a previous case study.
In 2008, members of a tour group experienced diarrhea and vomiting throughout a flight from Boston, Massachusetts, to Los Angeles, California.
The incident was so serious that the plane had to make an emergency landing three hours after takeoff.
The Centers for Disease Control and Prevention's investigation of the incident found passengers sitting in aisle seats were most likely to have contracted the illness as they were closer to the infected passengers who had been moving throughout the plane to get to the toilets.
There is some good news though - contrary to popular belief, Dr Gerba has said that germs are not spread through re-circulated air on planes.
"Usually the air is not much of a problem because it doesn't go back and forth—it goes around and is filtered," he said. "So when we've seen cases of influenza on air planes, it’s usually only the person right next to them—to the front, the back, or to the side—that has to worry."