Two patients remain in hospital in a stable condition following the ceiling collapse at London's Apollo Theatre, St Thomas' Hospital said.
Thirty-nine patients, including five children, were treated at the A&E department following the incident.
The remaining 37 were discharged throughout the night.
"The majority of patients had cuts and bruises, and a small number had fractures", the hospital said in a statement.
Once again the London fire brigade and ambulance service did amazing work last night at the #Apollo theatre,the real heroes of this city!
London Fire Brigade and London Ambulance Service have done an incredible job this evening... #ApolloTheatre
Nicola Aiken from Westminster Council said on BBC Radio 4 that, "District surveyors have attended and declared that the ceiling structure is sound and only plaster fell.
"Today we are waiting for the police to hand over the theatre to us as we are the health and safety authority for historic theatres in Westminster...
...and we will be doing checks of all historic theatres' consents and licensing today, in liaison with the Society of London Theatres, because we want to reassure theatre-goers that theatres are safe to attend.
"We will be carrying out the investigation as to why the accident happened in the first place, but that will take some time."
A spokeswoman for the National Theatre said:
"Performances of The Curious Incident Of The Dog In The Night-time today and tomorrow, Friday December 20 and Saturday 21, have been cancelled and ticket-holders will be contacted by whichever box office or ticket agency they booked through to arrange exchanges or refunds.
"As soon as we have more news about future performances, this information will be updated and ticket-holders contacted."
Theatre-goer Vegard Høgli tweeted a picture of the ceiling inside the Apollo Theatre as it was earlier this month.
A spokesman for Nimax Theatres, which owns the Apollo, described the ceiling collapse as a "shocking and upsetting incident" adding that their "thoughts are with the audience and staff" caught up in the incident and that an investigation into the cause was under way.
Police, ambulance and the Fire Brigade officers have said that 50 "low priority patients" have been taken to nearby London hospitals.
Officers confirmed that the scene at the Apollo Theatre ceiling collapse had been "fully evacuated" after "heavy ornate plastering fell from the roof" of the building.
A member of the London Ambulance Service added: "There are no life threatening injuries, [but there were] upper body injuries consistent with falling masonry."
Investigations have begun, but police said they had no reason to suspect any crimes had taken place.
Officers said that "road closures will need to stay in place for a number of hours" adding that the emergency services were under pressure because of the "busy, party season".
Simon Usborne, who was at London's Apollo Theatre when its ceiling collapsed last night, told Daybreak the audience initially thought it at was part of the show.
The Independent features writer said: "Not long before [the incident], one of the actresses who plays the mother of the main character walked through the audience to get to the stage ... shortly after she and the rest of the cast did stop and look up.
"You heard the noise, the cracks the bangs ... and then a split second later the entire view of the theatre ahead and stage disappeared because there was a huge curtain of dark grey dust and debris plummeting from above".
A member of the audience at the Apollo Theatre in London last night when the ceiling collapsed told Daybreak of an "almighty crash" before part of the roof came down on the audience.