A lift button swarms with nearly 40 times as many bacteria as a public toilet seat.
A study carried out in hotels, restaurants, banks, offices and airports found 313 'colony forming units' of bugs on every square centimetre of lift button. The equivalent surface area of toilet seat had only eight units.
The bacteria on the lift buttons could include stomach bugs such as e.coli, researchers say, according to the Daily Mail.
Nicholas Moon from Microban Europe, which carried out the research for the University of Arizona in the US, said: "In a busy building, a lift button can be touched by dozens of people who will have come into contact with all kinds of bacteria every hour."
"Even if the buttons are cleaned regularly, the potential for the build up of bacteria is high."
Previous studies have shown that a typical office desk harbours 400 times more bacteria than a toilet seat and computer keyboards have four times more germs than toilets.But Professor Hugh Pennington, a leading microbiologist in Britain, said: "Just because there are bacteria on a lift button it doesn't mean they are harmful to your health."
"The best way to protect yourself is to wash your hands before you eat or handle food."