Men should pee sitting down to avoid splashing their toothbrushes.
Men have been told to pee sitting down
Boffins have warned that urinating from a great height could send wee flying all over the bathroom and cause splashback that hits toothbrushes.
Scientist Tadd Truscott stressed that droplets could potentially spread E.coli bacteria unless the loo is three metres from the sink but the risk is removed if people sit down on the toilet.
Truscott, from the King Abdullah University in Saudi Arabia, said: "Water tends to have a large splash when droplets hit it from that height. That means a lot of splash can come out of the toilet.
"I was actually telling a friend when you pee into a toilet like that, you tend to pee on your toothbrush.
"If your toothbrush is one or two metres away, that's not good."