A US man who tried to shoot a mouse accidentally shot his girlfriend in the arm instead.

Donald Rugg, 43, spotted the mouse in his home in Confluence, Pennsylvania, and took a shot at it with his handgun.

But he missed the mouse and hit his girlfriend Cathy Jo Harris, 35, who had walked into the bullet's path, reports the Tribune Review.

Harris was taken to Somerset Community Hospital by her 16-year-old daughter, where she is said to be in a stable condition.