Driving with a heavy cold could be as dangerous as getting behind the wheel when you're drunk.
A new study showed that those who were under the weather had slower reaction times than people who had drunk up to four pints of beer.
A cold not only caused drivers to take longer to stop a car but made them drive too close to the vehicle in front and made them less aware of the danger of a collision.
And when they sneezed, they took their eyes off the road for up to three seconds.
"Having a cold is equivalent to drinking three or four pints and being over the limit," says Professor Andy Smith, of Cardiff University, who led the study.
"People with a cold had slower reaction times than those associated with drinking," he says.