Police were called to the Sugar House in Lancaster after reports of an assault.
They arrived at the student venue to find a woman unconscious after she had fallen.
The 20-year-old student had been involved in an altercation with a doorman and had fallen onto the floor.
She was treated at the scene by ambulance crews for a broken tooth, a black eye and bruises on her shoulder.
The incident was at 1.25am on March 21.