The Doctor Who and Torchwood star, who is currently playing the villain in US TV hit Arrow, was taken to hospital on Friday as a precaution after the accident at the SECC Clyde Auditorium. His understudy completed the matinee performance of Jack & The Beanstalk.
Sources claim Barrowman is shaken up but his injuries were not serious and he is expected to be back onstage on Saturday.
A spokesperson for the theatre says: "John is completely fine. He is just a little bit bruised."
Ironically, the actor's co-star, comedienne Janette Tough, aka Jimmy Krankie, suffered a fractured skull after falling from a mechanical beanstalk in the same panto in the same city in 2004.