One in five office mugs contain faecal matter, according to new research.
A study conducted by TotalJobs explained that this is because 25 per cent of people don't wash their hands after going to the loo while at work.
In light of these findings, Hygiene Doctor Dr Lisa Ackerley has given her advice on how to avoid these germs.
She said: ''Whatever you do, don't leave mugs or water bottles out overnight.
''Water is not sterile, and bacteria will build up overnight. Ideally, bring your own mug and bottle to work and don't share them with your colleagues.''
The study also discovered the average office desk has up to 400 times more bacteria than a toilet seat.