Thirty-five people were treated for minor injuries after thousands of fans braved the cold to watch X Factor finalists One Direction perform, ambulance staff said.
The boy band, mentored on the ITV1 show by Simon Cowell, performed a short open-air set in Wolverhampton's Queen Square yesterday.
West Midlands Ambulance Service said nearly 4,000 fans attended the show, with the first casualty being found more than three hours before the group took to the stage.
A spokesman said most of the injuries were caused by "the effects of the cold and over-excitement".
He said: "The band didn't come on stage until just before 8pm, but the
first casualty was found in Lichfield Street at 4.45pm with a head
injury. After treatment she was discharged on scene.
"Another five casualties were dealt with about half an hour later. Three hadn't eaten or drunk all day, one had felt faint and the fifth was hyperventilating.
"The latter two patients also had insufficient clothing on for the conditions. After treatment, getting warmed up and eating something, all five were discharged."
The spokesman added: "Just before the band took to the stage there was a surge in the crowd. A total of 28 people were lifted out over the barriers at the front. Eight were assessed by ambulance staff but did not require hospital treatment and went back into the crowd."
Fellow finalists Cher Lloyd, Rebecca Ferguson and Matt Cardle have also performed this week ahead of this weekend's finale.